Select the most appropriate option to substitute the highlighted segment in the given sentence. If there is no need to substitute it, select 'No substitution required'.
We have been waiting here for you since two hours.

Correct option is D

The correct substitution of the highlighted words is (d) for two hours.
Explanation: The sentence refers to a duration of time (“two hours”), and in such cases, the preposition “for” is used. “Since” is used for a specific point in time.
Grammatical rule used:
· Use ‘since’ when referring to a specific point in time (e.g., since morning).
· Use ‘for’ when referring to a duration (e.g., for two hours).
· Example: I have lived here for five years.
· Information Booster:
· "Since" is paired with simple time references, e.g., "since 2010", while "for" takes numerical duration.