Which of the following is equivalent to 30p^4q^3r + 42p^2r - 18p^2q^2r when it is completely factored?
A. 3pr(10p^3q^3 + 12p - 9pq^2)
B. 6(5p^4q^3r + 7p^2r - 3p^2q^2r)
C. 6p^2q^2r(5p^2q + 4)
D. 6p^2r(5p^2q^3 + 7 - 3q^2)