Name the intersection of plane bpq and plane cpq. 1) the planes do not intersect. 2) bp 3)pq 4)cq

Imagine two planes: they can be parallel or not. If they are parallel, then they don't have common points, but your planes have common points P and Q.

So, you can conclude that these two planes are not parallel, then they should intersect. Two planes intersect in a straight line and this line consists of all common points of both planes.

If planes are named BPQ (points B, P, Q do not lie on one straight line) and CPQ (points C, P, Q do not lie on one straight line), you can see two common points P and Q. Hence the intersection line must contain these two points and may be named as PQ (and points B and C do not lie on this line).

correct choice is C.