Question : Directions: In the following question, select the one different from the other three alternatives.
Option 1: 1
Option 2: 11
Option 3: 21
Option 4: 51
Correct Answer: 11
Solution :
Let's check the options –
First option:
1; 1 is not a prime number.
Second option:
11; 11 is a prime number.
Third option:
21; 21 is not a prime number.
Fourth option:
51; 51 is not a prime number.
So, only the second option differs from the other three options as 11 is the only prime number from the given options. Hence, the second option is correct.