**Rule: Understanding Idiomatic Expressions.** The idiom 'a red herring' refers to something that misleads or diverts attention from the central issue. 'Vague answers' are often used as a tactic to 'distract from the real issue.' Option (b) is the correct definition. Option (a) is the literal meaning. Option (c) is the opposite. Option (d) is unrelated.

**Rule: Understanding Idiomatic Expressions.** The idiom 'on its last legs' is used to describe something that is old, worn out, and close to failing. The suggestion to 'buy a new one' supports the idea that the old car is no longer reliable. Option (b) is the correct definition. Option (a) and (d) are the opposite. Option (c) is a detail that doesn't change the overall poor condition implied by the idiom.

**Rule: Understanding Idiomatic Expressions.** The idiom 'turn a blind eye' means to deliberately ignore something that you know is wrong. Ignoring a son's 'misbehavior' is a classic example of this. Option (c) correctly defines this intentional ignorance. Option (a) refers to a physical disability. Options (b) and (d) are actions of acknowledgment, not ignoring.

**Rule: Understanding Idiomatic Expressions.** The idiom 'touch-and-go' describes a situation that is very precarious and uncertain. The fact that they 'finally' reached an agreement implies there was a period of uncertainty where the outcome was in doubt. Option (c) is the correct definition. Option (a) is the opposite. Option (b) is a literal misinterpretation. Option (d) is irrelevant.

**Rule: Understanding Idiomatic Expressions.** The idiom 'keep one's head' means to stay calm and rational during a time of crisis or difficulty. Not 'panic-selling' during a 'market crash' is a clear example of remaining calm. Option (a) correctly defines this action. Options (b) and (d) describe negative reactions, the opposite of the idiom. Option (c) is a literal misinterpretation.

**Rule: Understanding Idiomatic Expressions.** The idiom 'all at sea' means to be in a state of confusion or to be lost and unsure of what to do. The context of a new intern needing a mentor for 'new software' supports this meaning of confusion. Option (c) is the correct definition. Option (b) is a literal misinterpretation. Options (a) and (d) are the opposite of being confused.

**Rule: Understanding Idiomatic Expressions.** The idiom 'a pillar of strength' refers to a person who is a source of great support and comfort to others in times of trouble. The word 'pillar' is used metaphorically to suggest someone who is strong and holds things up. Option (c) is the correct definition. Option (a) is the literal meaning of 'pillar.' Option (b) and (d) are the opposite of the idiom's meaning.

**Rule: Understanding Idiomatic Expressions.** The idiom 'draw a blank' means to fail to find something one is looking for or to be unable to remember something. In a police investigation, it means failing to find any leads or evidence. Option (a) is the correct definition. Option (b) is a literal misinterpretation. Option (c) is the opposite. Option (d) is a different meaning of 'blank'.

**Rule: Understanding Idiomatic Expressions.** The idiom 'bad blood' refers to feelings of ill will, resentment, or hostility between people. An 'argument' is a common cause of such feelings. Option (c) is the correct definition. Option (a) and (d) are literal misinterpretations. Option (b) is the opposite.

**Rule: Understanding Idiomatic Expressions.** The idiom 'against the clock' means to be rushed and have a very limited amount of time to complete something. A 'deadline' imposes a time limit, forcing one to work quickly. Option (a) is the correct definition. Option (b) is a literal misinterpretation. Option (c) is the opposite. Option (d) describes when one might work, but not the pace.