Select the most appropriate option to fill in the blank: She runs _____ athlete in her team.

Correct option is A

The correct comparative construction when comparing one individual to others in a group is "faster than any other." It follows standard grammar for comparative degree.
Explanation of options: (a) ✔ faster than any other – grammatically correct comparative structure. (b) ✘ fast than any – incorrect comparative usage. (c) ✘ fastest than – wrong structure; "fastest" is a superlative, not used with "than". (d) ✘ more fast than any other – incorrect form; the correct comparative is "faster".