the correct question in the attached figure
we know that
the probability
that a witness picks a particular person by chance-----> P=1/5
the probability
that all 7 witnesses would pick the same person-----> P=1/5^7=0.0000128
the answer is the option B 0.0000128
There are a variety of problems in which the number of witnesses change, for example
....find the probability that all 9 witnesses would pick the same person
in this case, the probability would be-------> P=1/5^9=0.000000512