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

Introduction / Context:
This question deals with the idiom “a live wire”. It appears in everyday English to describe certain types of people and is different from the literal meaning relating to electricity. Exams commonly test such idioms to see if you can interpret descriptive language and understand personality-related expressions accurately.

Given Data / Assumptions:

• Idiom: “a live wire”.
• We must choose the option that best captures its figurative meaning when used about a person.
• Options present several personality traits: industrious, brilliant, lively, active, sincere, efficient, shy, reserved.
• We assume the idiom is complimentary and energetic in tone.

Concept / Approach:
Literally, a live wire is a wire carrying electric current, full of energy and potentially dangerous. Figuratively, when we call someone “a live wire”, we mean that the person is very energetic, lively, and active, often full of enthusiasm and quick movement. The expression does not necessarily say anything about intelligence, sincerity, or reserved behavior. Therefore, the correct meaning focuses on liveliness and activity rather than moral or intellectual qualities.

Step-by-Step Solution:
Step 1: Recall typical usage, such as “She is really a live wire at parties” or “He is the live wire of the team”. Step 2: Observe that in such cases, the person is energetic, cheerful, and full of life. Step 3: Among the options, look for the phrase that emphasises energy and activity. Step 4: “Lively and active” exactly matches this energetic personality description. Step 5: Reject options that highlight qualities like sincerity, brilliance, or shyness, which are not central to the idiom.

Verification / Alternative check:
Insert possible meanings into example sentences: “He is a live wire in the office” meaning “He is lively and active in the office” makes perfect sense. Replacing it with “sincere and intelligent” or “shy and reserved” changes the tone and does not match how native speakers use the expression. This practical check reinforces that the idiom refers to a very energetic person who brings liveliness to a situation.

Why Other Options Are Wrong:
“Industrious and brilliant” focuses on hard work and high intelligence, not primarily on liveliness and excitement.
“Sincere and intelligent” is about honesty and intellect, which are not conveyed by the idiom “a live wire”.
“Sincere and efficient” describes reliability and effectiveness rather than energetic enthusiasm.
“Shy and reserved” is almost the opposite of a “live wire”, who is usually outgoing and animated.

Common Pitfalls:
Students may confuse “a live wire” with other expressions related to intelligence or hard work because they associate “live” with being “sharp” or “smart”. However, this idiom primarily captures energy and dynamism. A good way to avoid mistakes is to memorise idioms along with a short description like “very energetic person” and connect them to visual images, such as someone buzzing with energy at a party.

Final Answer:
The expression “a live wire” means “a lively and active person”.