The correct option is D contracts
The word 'expands' refers to becoming larger or more extensive.
Option A, shrinks refers to becoming smaller in size or amount.
Option B, reduces refers to making smaller in amount or size.
Option C, diminishes refers to making less.
Option D, contracts refers to decreasing in size or amount.
Thus, according to the meaning, the word 'contracts' is the opposite of the word 'expands'.