It used to be said that travel broadens one's outlook.

Answer: Option D

Broadens : become larger in distance from side to side; widen.
Restricts : put a limit on; keep under control.
Contracts : a written or spoken agreement, especially one concerning employment, sales, or tenancy, that is intended to be enforceable by law.
Shrinks : become or make smaller in size or amount.
Narrows : become or make less wide.

Antonym of Broadens is Narrows