Cells $C1,C2,$ and $C3$ contain the values $2,4,6.$ If cells $C1,C2,$ and $C3$ were selected, and autofill used to fill $C4,C5,$ and $C6,$ what would be the autofilled values?

$8,8,8$

$6,6,6$

$7,8,9$

$8,10,12$