In the following idiom and phrase question, choose the alternative that best expresses the meaning of the expression “smell a rat”.

Introduction / Context:
This idiom question requires you to interpret the figurative meaning of the expression “smell a rat”. Idioms are widely used in spoken and written English to add color and subtlety to language. In many competitive exams, idioms are tested to see if candidates can understand implied meanings beyond literal interpretations.

Given Data / Assumptions:

• Expression: “smell a rat”.
• We must pick the option that matches its figurative meaning in English.
• Options include both literal and figurative interpretations.
• We assume the idiom is used in a suspicious context, such as dealing with dishonesty.

Concept / Approach:
Literally, “smell a rat” might suggest noticing an unpleasant odor from a rodent. However, as an idiom, it means to suspect that something is wrong, dishonest, or not as it appears. When someone says, “I smell a rat,” they mean that they suspect a trick, deceit, or hidden wrongdoing. They do not mean that they detect an actual animal or merely misunderstand what is happening.

Step-by-Step Solution:
Step 1: Recall typical usage: “When they changed the contract at the last minute, I smelled a rat.” Step 2: Understand that in such contexts, the speaker suspects foul play or dishonesty. Step 3: Look at the options and find the one that refers to suspicion of trickery or deceit. Step 4: “Suspect a trick or deceit” directly expresses this sense. Step 5: Reject literal interpretations or those that refer to misunderstanding rather than suspicion.

Verification / Alternative check:
You can test the options by inserting them into the sentence: “When he suddenly offered help without any reason, I ____.” The only interpretation that fits natural usage is “suspected a trick or deceit”. Neither “detected bad smell” nor “chased an animal” works in such contexts. Therefore, the idiom clearly points toward suspicion of something dishonest or hidden.

Why Other Options Are Wrong:
“Detect bad smell” is the literal meaning and does not capture the idiomatic, figurative usage.
“Misunderstand” implies confusion or lack of understanding, which is not the same as feeling suspicious.
“See hidden meaning” may involve interpretation but does not necessarily imply deceit or trickery.
“Chase an animal” is again literal and unrelated to the idiomatic expression.

Common Pitfalls:
A frequent mistake is taking idioms literally or translating them word-for-word into one's own language. Another pitfall is confusing idioms with similar themes, such as “rat race” or “like a rat in a trap”, which have different meanings. To master idioms, always learn them with their typical contexts and a short example sentence so the figurative meaning becomes clear and memorable.

Final Answer:
The idiom “smell a rat” means “to suspect a trick or deceit”.