Which option will replace the '?' B_2CD, BC_3D, ? , B_5CD, BC_6D

We have,

$B_2CD, BC_3D, ? , B_5CD, BC_6D$

Logic, the number is getting repeated in increasing order after every alphabet in each term.

So, Now the number will be along with D in the answer term.

$B_2CD, BC_3D, $BC\, D_4$ , B_5CD, BC_6D$