Given that, $abca \_ bcaab \_ aa \_ caa \_ c$
We can make the pattern, like this,
$abca \mid \_ bca\mid ab \_ a \mid a \_ ca \mid a \_ c$
Now, we can fill the blank,
$abca \mid {\color{Red}a} bca\mid ab {\color{Blue}c } a \mid a {\color{Orange} b} ca \mid a {\color{Magenta} b} c$
So, the correct answer is $(C).$