Choose from the options lettered A- E the one that is most nearly opposite in meaning to the word or…

Analyze the question

The sentence is: "The hitherto adequate fuel supplies were found to be __ during the industrial action." The question asks for the word most nearly opposite in meaning to the italicised word. The italicised word appears to be adequate. (The italics don't show in the text you pasted, but the sentence structure makes this the likely target.)

Concept

• Adequate means enough or sufficient.
• Hitherto means "up until now". So the sentence says fuel supplies that had been enough up to now turned out to be not enough during the strike. This contrast fits the structure of the sentence.
• An antonym of adequate is therefore a word meaning "not enough".

Checking the options

• A. enough is a synonym of adequate, so it is wrong.
• B. inconvenient means causing trouble. It does not mean the opposite of adequate.
• C. insufficient means not enough. It is the direct antonym of adequate and fits the sentence.
• D. rationed means shared out in limited amounts. This is a consequence of shortage, not an antonym.
• E. restricted means limited. It is related, but it is not the opposite of adequate.

Answer: C. insufficient

Tip: In antonym questions, first find the word's meaning, then check whether the sentence supports a contrast. Words like hitherto, however and but signal a change. Also beware of options that are merely related to the topic, such as rationed and restricted. They are not true opposites.