A light spring balance hangs from the hook of the other light spring balance and a block of mass M kg hangs from the former one. Then the true statement about the scale reading is
a. Both the scales read M/2 kg each
b. Both the scales read M kg each
c. The scale of the lower one reads Mke and of the upper one zero
d. The reading of the two scales can be anything but the sum of the reading will be M kg​