Apause in the score of a concerto, preceding a cadenza, is indicated by a

The appropriate response is fermata. Fermata is a sign which is in Italian name, which in English is ordinarily called a Pause, and means that the note over which it is put ought to be hung on past its characteristic length. It is some of the time put over a bar or twofold bar, in which case it suggests a short interim of hush.

The correct answer is c