Consolidate :

Answer: Option A

Expand : become or make larger or more extensive.
Destroy : end the existence of (something) by damaging or attacking it.
Build : construct (something) by putting parts or material together.
Weaken make or become weaker in power, resolve, or physical strength.
Consolidate : make (something) physically stronger or more solid.

Antonym of Consolidate is Weaken.