Select the option that will improve the underlined part of the given sentence.
Tarika dances swiftest than others and misses all the steps.

The sentence uses the conjunction than, which indicates that a comparison is being made between Tarika and others.
Swiftest is a superlative adjective, which is used when comparing more than two entities without the word "than".

Swifter is the comparative form of the adjective/adverb, which is correctly used with than to compare two entities or groups (Tarika vs. others).

Therefore, "swiftest" must be replaced with swifter to make the sentence grammatically correct.