IKMC 2014 - Grades 11-12 - Self-study Question 21

Question 21

Let $a,b,c$ be distinct nonzero real numbers and $n$ a positive integer. The products $(-2)^{2n+3}a^{2n+2}b^{2n-1}c^{3n+2}$ and $(-3)^{2n+2}a^{4n+1}b^{2n+5}c^{3n-4}$ have the same sign. What must be true?

$a>0$
$b>0$
$c>0$
$a<0$
$b<0$