I think the answer would be c
The store display rotates 40 times every half hour meaning that it will rotate 80 times every hour. To find how many times it will rotate in 4 hours, you can do 80 times 4. This is 320 rotations.
Also, please try and correctly list your question as this does not pertain to this subject.
If they had just lost a loved one and they were talking to you about it, you would probably hear emotion in their voice.
I think it would be 18 because it moved a total of 18=12+6