Correct Answer: 93

Solution : Let's check the options –
First option: 71; 71 is divisible only by 1 and 71. So, it is a prime number.
Second option: 83; 83 is divisible only by 1 and 83. So, it is a prime number.
Third option: 89; 89 is divisible only by 1 and 89. So, it is a prime number.
Fourth option: 93; 93 is divisible by 1, 3, 31, 93. Due to more than two factors, it is not a prime number.

The fourth option does not follow a similar pattern as the other options. Hence, the fourth option is correct.