A light string of mass m and length L has its ends tied to two walls that are separated by the distance D . Two objects each of mass M are suspended from the string as shown in figure given . if a wave pulse is sent from point A find speed is AB string

Question

$(a)\;\sqrt{\large\frac{2l(2D-L)}{\sqrt{4D^2-4DL}}}\qquad(b)\;\sqrt{\large\frac{(2D-L)}{4D^2-4DL}}\qquad(c)\;\sqrt{2l(2D-L)}\qquad(d)\;None$