Given the vectors $a = (1, 2, 3)$ and $b = (1, -1, 2)$, what is the dot product $a \cdot b \cdot a$?

$4$
$5$
$14$
$(7, 1, -3)$
$(-7, -1, 3)$
$(7, -1, -3)$
$(1, -2, 6)$
$(5, -5, 10)$
does not exist