Moments of solitude and silence helped the poet to concentrate on his poetic combination.

Answer: Option D

Concentrate : focus all one's attention on a particular object or activity.
Confound : cause surprise or confusion in (someone), especially by not according with their expectations.
Disturb : interfere with the normal arrangement or functioning of.
Contradict : deny the truth of (a statement) by asserting the opposite.
Distract : prevent (someone) from concentrating on something.

Antonym of Concentrate is Distract