Final answer:
None of the provided words 'best,' 'surprising,' 'moved,' or 'told' is a gerund. The sentence does not contain a gerund, as a gerund is a verb ending in '-ing' that functions as a noun, which is not applicable to any of these words.
Step-by-step explanation:
The gerund in the sentence 'My best friend told me a surprising story about her life before she moved here.' is 'moved.' A gerund is a verb form that ends in '-ing' and functions as a noun. Although 'moved' seems like a possible candidate as it is verb, it does not end in '-ing' thus it is not a gerund. In this sentence, there is actually no gerund present since none of the verb forms function as a noun or end with '-ing.' Therefore, none of the options given (best, surprising, moved, told) are gerunds. 'Surprising' is an adjective modifying 'story,' and 'told' and 'moved' are verbs in the past tense. 'Best' is also an adjective modifying 'friend.'