Correct : c

The most appropriate option is:
c) resolve
So the complete sentence is: "Despite his initial hesitation, Rehman's resolve to contribute to the success of the project never wavered."
Explanation:
Resolve means determination or firmness of purpose, which fits the context of unwavering intent despite hesitation.
Ambivalence means having mixed feelings, which does not fit with "never wavered."
Satisfaction is about contentment, not determination.
Revolve is a verb and does not make sense in this context.