to implement the previous state table then how many flip flops you need :

Select one:

4 flip flops with one external input and one output

2 flip flops with one external input and one output

2 flip flops without external input or output

none of the above

Present State Next State Input x Output 0 0 1 0 0 0 o 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 0 0 1 0 1 0 1 0 1 0 1 0 0 0 0 1 o