For the function to be continuous at $x = 1$, the left-hand limit and right-hand limit must be equal at $x = 1$.
The left-hand limit is:
\[
f(1) = 3(1) - 2 = 1
\]
The right-hand limit is:
\[
f(1) = 2(1)^2 + a(1) = 2 + a
\]
Setting these equal, we get:
\[
1 = 2 + a \quad \Rightarrow \quad a = -1
\]
Thus, the correct answer is $a = -1$.