A mass `m`, which is attached to a spring with spring constant `k`, oscillates on a horizontal table, with amplitude `A`. At an instant when the spring is streched by `sqrt(3) A//2`, a second mass `m` is dropped vertically onto the original mass and immediately sticks to it. what is the amplitude of the resulting motion-
A. `sqrt((3)/(2))A`
B. `sqrt((7)/(8))A`
C. `sqrt((13)/(16))A`
D. `sqrt((2)/(3))A`
