If you waver at the last minute, you shall face failure.

Answer: Option D

Resolve : settle or find a solution to (a problem or contentious matter).
Decide : come or bring to a resolution in the mind as a result of consideration.
Settle : resolve or reach an agreement about (an argument or problem).
Hesitate : pause in indecision before saying or doing something.
Waver : be undecided between two opinions or courses of action.

Synonym of Waver is Hesitate