Correct option is D
The correct option to fill in the blank is (d) assuming.
•
Assuming: means taking something for granted or accepting something as true without proof. In this context, it refers to someone wrongly believing that it’s always the speaker who messes up the work.
• Example: Can you please stop assuming it’s me who keeps messing up the work?
Meanings of the other given options:
• (a)
Assuring: Making someone feel confident or certain about something.
• (b)
Amusing: Causing laughter or providing entertainment.
• (c)
Adopting: Legally taking another's child and bringing it up as one's own, or beginning to use or follow an idea, method, or course of action.