Ans: A
$\begin{array}{cl}
& (3a + 2b)(4a – 5b) – a(6a + 4b) \\
= & (3a + 2b)(4a – 5b) – 2a(3a + 2b) \\
= & (3a + 2b)(4a – 5b – 2a) \\
= & (3a + 2b)(2a – 5b)
\end{array}$
$\begin{array}{cl}
& (3a + 2b)(4a – 5b) – a(6a + 4b) \\
= & (3a + 2b)(4a – 5b) – 2a(3a + 2b) \\
= & (3a + 2b)(4a – 5b – 2a) \\
= & (3a + 2b)(2a – 5b)
\end{array}$
