His sententious reply impressed the visitor.

Answer: Option D

Sharp : (of an object) having an edge or point that is able to cut or pierce something.
Quick : moving fast or doing something in a short time.
Insipid : lacking flavour; weak or tasteless.
Meaningful : having meaning.
Sententious : given to moralizing in a pompous or affected manner.

Synonym of Sententious is Meaningful