Question: Celeb worked very hard on his last work because he hoped for an _____ in his salary.
Correct Answer: increase
This question tests vocabulary. "Increase" means a rise in amount or number, which fits the context of hoping for a higher salary after hard work.

Incorrect Answers:
- inquiry - Means a request for information, not relevant to salary.
- indifference - Means lack of interest, opposite of what's expected here.
- inclusion - Means being part of something, unrelated to salary changes.