If \(\displaystyle z=1+\sqrt{3}i\) is a solution to the equation \(\displaystyle z^3-a=0,\ a\in\ c\) then the other two solutions are?

I know one of them must be \(\displaystyle z=1-\sqrt{3}i\) as the coefficient of \(\displaystyle z^3\) is real. But I'm not sure how to find the last solution.

From the options (mc question) it seems that it's either \(\displaystyle z=2\) or \(\displaystyle z=-2\).

Thanks for your help