1. (3x)^2 = 4 or 8 or 12 or 16 or 20 or 24 or 36 or 72..whatever. We can conclude that x will be a odd number or a fraction. Surely not even. Thus, Suff.
2. 3x +2 = 8 or 16 or 24 or 32 whatever. We can confirm that x can be even or fraction. Thus, Insuff.
I think x shd be even in Statement 1.
Statement 2 seems sufficent to answer the question. Becasue that condition is true, then x shd be even as no odd number substitute into 3x+2 will be divisible by 8
So it shd be D