Three identical small conducting spheres A, B, and C are initially isolated. Sphere A carries +15μC, sphere B carries −9μC, and sphere C is neutral. The following sequence occurs:
1. A is touched to B and then separated.
2. B is touched to C and then separated.
3. C is touched to A and then separated.
After this sequence, what is the final charge on sphere C?
a) +1.5μC
b) +2.25μC
c) +2.0μC
d) +3.0μC