Im so confused with this physics question; Can someone help me

Three rods of different materials P, Q, and R are charged by various methods. When the rods are brought near each other, the rods, P and Q repel each other, while the rods P and R attract each other. Which of the following could be the sign of the charge on the rods?

a. Rod P -, Rod Q +, Rod R -
b. Rod P -, Rod Q +, Rod R -
c. Rod P -, Rod Q -, Rod R +
d. Rod P -, Rod Q -, Rod R -

I do realize that A and B are the same answers.

Problems like these should be done one step at a time. It's much easier that way.

P and Q repel each other, therefore their charges must be the same. Following that logic, a and b are out.

P and R attract each other, therefore their charges must be opposite.

The correct answer satisfies both scenarios. That answer is c.