Your answer would be the second option, (3a - 4)(a + 3).
We can see that this is the correct answer as if we expand it using FOIL, we get 3a² + 5a - 12:
(3a × a) + (3a × 3) + (-4 × a) + (-4 × 3) = 3a² + 9a - 4a - 12
= 3a² + 5a - 12.
I hope this helps!
