Each week we post Verbal or Math question on our Facebook page. Answer this question to win a GMAT Club tests subscription.
Last week's Math question:
Nine family members: 5 grandchildren (3 brothers and 2 sisters) and their 4 grandparents are to be seated around a circular table. How many different seating arrangements are possible so that 2 sisters are seated between any two of the three brothers?
A. 120
B. 480
C. 1440
D. 2880
E. 8640