In this idiom and phrase question, out of the four alternatives select the option which best expresses the meaning of the idiom "At large".

Introduction / Context:
This question tests your understanding of English idioms. The phrase "at large" is often used in news reports and formal writing, and it has a specific idiomatic meaning that is different from the literal sense of the words "at" and "large". You are required to identify the meaning of this idiom from the given options.

Given Data / Assumptions:

- Idiom: "At large". - Options describe different possible meanings. - You must select the meaning commonly used in standard English, especially in crime and news contexts.

Concept / Approach:
Idioms are expressions whose meanings cannot be fully understood from the individual words. "At large" in everyday and journalistic English usually refers to a criminal or suspect who has not yet been caught and is still free. It can also sometimes mean "in general" when used in other contexts, such as "society at large", but in exam questions about crime and description of persons, the most common tested meaning is "escaped or not yet captured". You should look at the answer choices and match them against this well known usage.

Step-by-Step Solution:

Verification / Alternative check:
Place each option into a typical sentence to see what fits. "The escaped prisoner is still at large" clearly means "The escaped prisoner is still not captured." Substituting "a very big opportunity" or "a big appetite" makes the sentence absurd. "Society at large" is another common phrase in which "at large" means "in general", but that nuance is not provided in the options. Among the given choices, only the criminal related meaning fits standard usage and typical exam patterns.

Why Other Options Are Wrong:
The idea of a big opportunity, big heart, big appetite, or strong influence is not linked with the idiom "at large" in conventional English. While individual words like "large" can suggest size or importance, idiomatic expressions must be learned as fixed units. The exam expects the familiar crime reporting sense. Therefore, all options except the one about an escaped or uncaptured criminal distort or misinterpret the expression.

Common Pitfalls:
Students sometimes try to guess the meaning of idioms from the literal meanings of the words. This can be misleading because idioms often have a history or special usage that is not obvious. Another pitfall is overgeneralising from one context like "society at large" and trying to force that meaning into options that do not match exactly. The safest strategy is to remember common collocations that you have seen in newspapers and books and test the options against that memory.

Final Answer:
The idiom "At large" means "a criminal escaped or not yet captured", so the correct answer is "A criminal escaped or not yet captured."