Select the most appropriate option to improve the bold part of the sentence.
I am used to eat late at night.

Correct option is C

The correct substitution of the highlighted words is (c) to eating.
Explanation: With the structure be used to + noun/gerund (V-ing), “used to” functions like a preposition meaning accustomed to. Therefore, after “am used to”, we need a gerund, not the base verb. Hence, “I am used to eating late at night.” is correct.
Grammatical rule used:
· be/get used to + noun/gerund = be/become accustomed to something.
· used to + base verb expresses a past habit/state that no longer holds (e.g., I used to eat late).
· Here, the meaning is accustomed now, so be used to + eating is required.
· Example: She is used to working long hours. / He used to work nights (past habit).
· Information booster / exceptions:
· get used to indicates the process of becoming accustomed (e.g., I’m getting used to waking up early).
· Remember: in be used to, to is a preposition, so it takes a gerund/noun; in used to + V1, to is the infinitive marker.