Final answer:
The synonym for "twirl" is "rotate," since both words describe the action of moving in a circle or spinning around an axis.
Step-by-step explanation:
The word synonym refers to a word or phrase that means exactly or nearly the same as another word or phrase. When considering the word "twirl" which is a verb, we are looking for another verb that has a similar meaning. The correct synonym for "twirl" is "rotate" (option a). Both "twirl" and "rotate" describe the action of something moving in a circle or spinning around an axis. The other options, "wriggle" (option b), "distort" (option c), and "zigzag" (option d), do not share the same meaning of moving in a circular motion or spinning.