Select the most appropriate option that can substitute the underlined segment in the given sentence. If there is no need to substitute it, select ‘No substitution’.
He was the fastest between all the contestants.

The correct option to substitute the underlined word is amongst.

Explanation:

In English grammar, preposition usage depends on the number of items or people being referred to:

1. 'Between' is used when comparing or referring to two distinct items, places, or people (e.g., "between the two brothers").

2. 'Among' or 'Amongst' is used when referring to more than two people or things, or a group as a whole (e.g., "amongst all the contestants").

Since the sentence refers to "all the contestants" (which implies a group of more than two), the preposition 'between' is incorrect and should be replaced by 'amongst'.

Therefore, the corrected sentence reads:
"He was the fastest amongst all the contestants."