Factoring!!! Please help. Picture included

3yz²-4y²z+6y³-2z³
First group the terms with the coefficients 3 and 6 and 4 and 2 together.
3yz²+6y³-4y²z-2z³
And then factor the GCF from the first two terms and the last two.
3y(z²+2y²)-2z(2y²+z²) The two binomials match so we can group 3y and -2z
(3y-2z)(z²+2y²)
answer: C