If num is an int which expression always evaluates to true if num holds an odd number

1) Num%2==0

2) Num%2 <0

3) Num%2==1

4) Num/2==1

The answer is 2) Num%2==1.

The modulus operator (%) divides the left hand side by the right hand side and returns the remainder.

Examples:

3%2=1 : 2 goes into 3 once, with 1 remaining.

5%2 = 1 : 2 goes into 5 twice, with 1 remaining.

11%2 = 1 : 2 goes into 11 five times, with 1 remaining.