Answer:
The answer should be C.
Explanation:
A. What have been the achievements of the American space program?
This question is too broad, containing all of the achievements of a large program.
B. What alternative fuels offer our best prospects in the next ten years?
This is also too broad, asking about the next ten years.
C. How do the symptoms of a heart attack differ from those of a stroke?
This is the answer because you are asking about a fact that many people do not know, (and might want to know) the answer to. Not too broad, nor too narrow.
D. How many American jobs pay only the minimum wage and offer no benefits?
This question asks about all of America, and that is very broad.
- Hope this helps, Good Luck.
My best bet would to go with 'were' because they sound similar and it just seems more professional.
<span>Both may occur when plates slide past each other.
hope it helps</span>