Chọn câu trả lời đúng

But the sea has become so polluted from oil spills and factory wastes that the fish are dying. This is not only killing the fish but is also affecting those people who eat fish.
Seldom do you find a place nowadays that is not polluted
The word “This” in the passage refers to _________
1 điểm
A. pollution
B. oil
C. factory
D. sea