Idioms and Phrases - Verbal and Reasoning

In the following questions four alternatives are given for the idiom/phraseitalicised and underlinedin the sentence. Choose the alternative which best expresses the meaning of idiom/phrase.
Q1:

The popularity of the yesterday's superstar is on the wane.

A at its peak

B at rock bottom

C growing more

D growing less

ANS:D - growing less

No answer description is available.