The correct option is C churlish
The word 'gracious' refers to being courteous, kind and pleasant, especially towards someone of lower status.
Option A, benign refers to being gentle and kind.
Option B, infrastructure refers to the structure or framework of something.
Option C, churlish refers to being rude in a mean-spirited and surly way.
Option D, wasteful refers to using or expending something of value carelessly or extravagantly.
Thus, according to the meaning, the word 'churlish' is the opposite of the word 'gracious'.