It's zero. it's easy to see if you consider any point before the collision. Since momentum is conserved through any collision (as long as you include all objects in your system), the total momentum then is equal to the momentum after. Taking both objects as a single system, the angular momentum is given by the rotational component of disk 1 + translational component of disk 1 moving in reference to the point p (disk 2 does not move with respect to point p, so it doesn't matter). The first term is straightforwardly

, and the second term is

. These are equal, and considering the system shows they're opposite (I guess you could also keep track of signs from the dot and cross products, but i never do).

EDIT: should say the fastest way to do this question is to eliminate B, C, and E (b and c are equivalent, and E makes no sense). Then A is less than

and D is more. Since the disk is revolving opposite its motion we know it's less, so the answer must be A.