A class of 4 Gangs is to be chosen from five Gangs.Each Gang contains 2 people.What is the number of different Gangs that can be chosen if two people who are in same gang to each other cannot both serve on the class?
Choose the correct choice from the following options:
A) 840 B) 960 C) 60 D) 720 E) 1050
Each GANG can send only one representative to the class. Let's see in how many ways we can choose 3 gangs (as there should be 3 members) out of 4 to send only one representatives to the class: 5C4=60.   But each of these 3 gangs can send two persons : 2*2*2*2=2^4=16.   Total # of ways: 5C4*2^4=960.   Answer: 960.
<result>B</result>
A class of 4 Gangs is to be chosen from five Gangs.Each Gang contains 2 people.What is the number of different Gangs that can be chosen if two people who are in same gang to each other cannot both serve on the class?