Answer: C. 45%
"if it is known to be lemon" means we ignore any other flavor. I recommend covering up the other values, or you could highlight just the lemon column.
We have 9+11 = 20 lemon total. Of this 20 total, only 9 lemons have a chocolate center. So 9/20 = 0.45 = 45% of the lemon candies have a chocolate center.