This is a YES/No type of DS question. Substituting values would be the best way to solve.
Constraint: a is an integer. So a can range from -\(\infty\) to +\(\infty\)
Question: Is \(\frac{a}{2}\) even.
This here might suggest that a has to be 0 or even, but that is not correct if a = 2, 6, 10 as \(\frac{a}{2}\), will be odd for these numbers.
So, we need to know if a is a multiple of 4 or if a is 0.
Statement 1: 3a is even
Since 3a is even and we know that Odd * Even given an even number, so a is even (0,2,4...)
If a = 2, then \(\frac{a}{2} = 1\) which is odd
If a = 4, then \(\frac{a}{2} = 2\) which is even
Therefore Statement 1 Alone is Insufficient. Answer options could be B, C or E
Statement 2: 4a is even.
This indicates that a can be even or odd as Even * Even = Even and Even * Odd = Even.
a = 1, \(\frac{a}{2} = \frac{1}{2}\) which is neither even nor odd
a = 2, \(\frac{a}{2} = 1\) which is odd
Therefore Statement 2 Alone is Insufficient.
Combining Both Statements: We get that a is definitely even, but we cannot say that it is a multiple of 4.
Therefore Both Statements together are Insufficient.
Option EArun Kumar