What is the value of $$a^{2} + 4b^{2} + 9c^{2} - 4ab + 12bc - 6ca$$?

A

$$(a + 2b - 3c)^{2}$$

B

$$(2a - b - 3c)^{2}$$

C

$$(2b - a - 3c)^{2}$$

D

$$(a - 2b - 3c)^{2}$$