Seven friends are riding the bus to school:
- Cha and Bai are on 2 different buses.
- Bai, Abu and Don are on 3 different buses.
- Don, Gia and Fan are on 3 different buses.
- Abu, Eva and Bai are on 3 different buses.
- Gia and Eva are on 2 different buses.
- Fan, Cha and Gia are on 3 different buses.
- Cha and Eva are on 2 different buses.
What is the least possible number of buses on which the friends could be riding?
Answer Choices
A. 3
B. 4
C. 5
D. 6
E. 7