One of the prerequisites for success in examination is burning the midnight oil.

Step 1: Analyze the question The sentence uses an idiom: "burning the midnight oil." You are asked to pick the option that best explains what the sentence means.

Step 2: Explain the concept "Burning the midnight oil" means working or studying late into the night. It comes from the days before electricity, when people used oil lamps to work after dark. A "prerequisite" is something required beforehand, or a necessary condition.

So the sentence says: One of the necessary conditions for success in exams is studying late into the night.

Step 3: Evaluate the options

• A. needs to study late into the night. This matches the idiom's meaning exactly. ✔
• B. should stay awake all day. The idiom is about late at night, not all day. ✘
• C. one should burn all the candles. This reads the idiom literally. ✘
• D. one needs to study at will. "At will" means whenever you like, which has nothing to do with working late. ✘

Step 4: Answer The correct option is A.

Tip: In idiom questions, never take the words literally. Ask yourself what the phrase figuratively means, then eliminate options that repeat the literal images (candles, oil, fire). Other common idioms are "to burn the candle at both ends" (to exhaust yourself by doing too much) and "to hit the books" (to study hard).