Came across this problem on a math competition.

The equation $\displaystyle 3x^2 + 4x + k = 0$ has two imaginary roots. Which of the following is a true statement about the value of $\displaystyle k$?

a) $\displaystyle k < 0$

b) $\displaystyle k < -2$

c) $\displaystyle k > 2$

d) $\displaystyle k > 0$

I'm having a hard time setting up a condition for k.