Considering that the expression 5a + 5a + 5ab + 5ab is equivalent to 10a + 10ab, what is an equivalent expression for 6abc + 6abc + 6abc?
A18abc
B18a + 18b + 18c
C18a + 18ab + 18abc
D216a + 216b + 216c
A18abc
B18a + 18b + 18c
C18a + 18ab + 18abc
D216a + 216b + 216c