For part b) DIV/P = .04 and DIV/EPS = .60. Use those two equations to find EPS/P.
Then use EPS/P = r(1 - PVGO/P) to find PVGO/P. This will let you know what percentage of the price future investment opportunities was. So, the price will drop by (PVGO/P)%.
For part c) If the expected return on new investments is the same as the market capitalization rate, then the PVGO = 0. So, the price would be the same as in part b).