Correct Answer:
D. to explain
Expound means to explain in detail.
- Correct answer - to explain: it has the same meaning as Expound.
- to be angry: to feel rage - wrong, it does not mean the same as Expound.
- to release: to set free - wrong, it does not mean the same as Expound.
- to expel: to drive out - wrong, it does not mean the same as Expound.