Explanation

(c)
Given, $(x + iy)^{1/3} = 2 + 3i$
$\Rightarrow \ \ x + iy = (2 + 3i)^{3}$
$= 8 + 36i + 54i^{2} + 27i^{3}$
$= - 46 + 9i$
Equating real and imaginary parts from both sides, we get
$x = - 46,\ \ \ y = 9$
$\therefore\ \ \ 3x + 2y = - 138 + 18 = - 120$