The teacher said that Ali's essay was full of many redundant details?

Analyze the question

You are asked for the word opposite in meaning to "redundant" in the sentence: "Ali's essay was full of many redundant details."

Explain the concept

"Redundant" means unnecessary, superfluous, or more than is needed. Details that are redundant add nothing, because the point has already been made or they are not required.

Solution

Check each option against "redundant":

• A. unexplained: This means not made clear. It has nothing to do with whether something is needed, so it is not an opposite.
• B. strange: This means unusual. It is unrelated.
• C. necessary: This means needed or essential. It is the direct opposite of "unnecessary/superfluous," so it fits.
• D. useful: This is close, and it is the tricky option. Something redundant can still be "useful" in a general sense, but it is not needed in that context. "Necessary" is the stronger and more exact antonym, because redundancy is about being not required.

Both C and D are plausible, but "redundant" literally means "not necessary," so its precise opposite is "necessary.

Answer: C. necessary

Exam tip

For antonym questions, first replace the word with a simple definition. Here, redundant = "not necessary." Then look for the option that reverses that definition ("necessary"). When two options seem close, choose the one that reverses the exact meaning, not just the general idea.