The answer would be d. malfunction. (Supposing that the underlined word was failure). :)
Firstly read the question clearly and take note of all the information's provided. this will make solving the question easier.
Number of roses that the florist has = 130
Percentage of roses that the florist has = 65%
Let us assume the number of roses that the florist has in total = x
Then
65x/100 = 130
65x = 130 * 100
65x = 13000
x = 13000/65
= 200
So the florist had 200 flowers in all. I hope the procedure is clear enough for you to understand.
B. The sentence needs a clearer controlling idea