In the series : 7  8  9  7  6  5  3  4  2  8  9  7  2  4  5  9  2  9  7  6  4  7
Which figures have equal frequence ?

Answer: D. 865

In the given series, 2 occurs 3 times; 3 occurs once; 4 occurs 3 times; 5 occurs 2 times; 6 occurs 2 times; 7 occurs 5 times; 8 occurs 2 times and 9 occurs 4 times.
Clearly, the frequency of 5, 6 and 8 is the same i.e. 2.