Gradualism is a pattern of evolution in which
a. a single species evolves into several closely related species.
b. several distantly related species develop similarities.
c. a species evolves at a slow, steady pace.
d. a species has periods of little evolution interrupted by periods of rapid evolution.

The correct answer is-

C. a species evolves at a slow, steady pace.

Gradualism can be describesd as a pattern/ theory of evolution by which already existing species give rise to new species by means of slow/ gradual and steady changes instead of major and abrupt changes.  

Over long period of time, the small changes (that are beneficial for their survival) result in new species.

Example- Tiger that is evolved pattern of stripes ( which give them better advantage to hide in tall grass).

Thus, option C)  a species evolves at a slow, steady pace.  is the right answer.

c is the correct answer hope this !