A mass body $m$ slides without friction on the flat (and inclined from an angle α to horizontal) surface of a mass block $M$ under spring action, shown in the figure. This spring, of elastic constant k and natural length $C$, has its ends respectively attached to the mass body m and the block. In turn, the block can slide without friction on the flat and horizontal surface on which it rests. The body is pulled to a position where the spring is stretched elastically to a length $L (L>C)$ such that upon release the body passes the position where the tensile force is zero. In this position, the block velocity modulus is:
a)$\sqrt{\frac{2m[\frac{1}{2}k(L-C)^2-mg(L-C)sin(\alpha)}{M^2[1+sin^2(\alpha)]}}$
b)$\sqrt{\frac{2m[\frac{1}{2}k(L-C)^2-mg(L-C)sin(\alpha)}{M^2[1+tan^2(\alpha)]}}$
c) $\sqrt{\frac{2m[\frac{1}{2}k(L-C)^2-mg(L-C)sin(\alpha)}{(m+M)[(m+M)tan^2(\alpha)+M]}}$
d)$\sqrt{\frac{2m[\frac{k}{2}k(L-C)^2]}{M^2[1+tan^2(\alpha)]}}$
e) 0
I tried to do $\alpha = 0$, replace in alternatives, and see that the alternatives are just one change. Ae solve in the plan where I considered $\alpha = 0$
Can someone help me? Thank you very much in advance!