I think state table mean, the information about inputs and on seeing what inputs, we can know about the states of the flip-flop, in the sense what is the present and next state of the flip-flop.
So, for each of any of the M flip-flops, we have to write the present as the next state of the flip-flop.
hence for M=1, we should have two entries, one for present state and one for next state.
So, for M flip-flops, there will be 2M columns for flip-flop state information.
If there is one input, then there will be 1 column.
so for N input, we should have N columns.
so, total columns in state table = 2M + N
so correct option is C...