Answer:
High average wind speeds
Step-by-step explanation:
Method 1:
To get this answer, we will need to do process of elimination. We need to eliminate the answer(s) we know that's wrong.
I eliminated No wind (B), and Constant wind (A).
That would leave is with High average wind speeds and Low average wind speeds. In the question, it says "For a wind farm to be EFFECTIVE".
Because of the word effective, High average wind speeds is correct.
Method 2:
For this, we will need to think. Constant winds would be too much for a wind farm to handle, and no wind would be pointless to even have one there. Low average wind speeds would be too poorly for an effective wind farm, so D is correct.
Hope i gave you back some of your brain cells! :D
-Snooky