In the following question, out of the given four alternatives, select the alternative which best expresses the meaning of the Idiom/Phrase.

To twiddle one’s thumbs

To be idle

The idiom "to twiddle one's thumbs" means to be idle or to do nothing. So the answer is (1) To be idle.

The other options do not fit the meaning of the idiom.

• To play safe means to avoid taking risks.
• To waste one's resources means to use them up without getting anything in return.
• To show no mercy means to be cruel or unsympathetic.