Hey there!
First, make sure you know what an abstract noun is.
Abstract Noun-<span>a noun denoting an idea, quality, or state rather than a concrete object.
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In this case, the answer is D(Logic is easily understood)
Habit is to custom as transition is to volta
.
That would be false, wouldn't it?
A mirage is an optical phenomenon
The word I can think of that best fits instead of "mirage" would be oasis, though I could be wrong.