Question

in the figure given below, a man of true mass M is standing on a weighing machine placed in a cabin. The cabin is joined by a string with a body of mass m. Assuming no friction and negligible mass of cabin and weighing machine, the measured mass of man is? (i.e normal force on man is)?
a) measured mass of man =Mm/(m +M)
b)accelaration of man =mg/(m + M)
c) accelaration of man =Mg/(M+m)
d) measured mass of man = M.