C FORM
It is issued by VAT department to the registered dealer who makes interstate purchases of those goods which are mentioned in his RC (registration certificate). While doing transaction purchasing dealer furnish this form to selling dealer in course of interstate purchase to get exemption/reduction in sales tax rate. It is defined under section 8(1) of CST act 1956.
Form "D"
Form "D" is a certificate under CST act. If government purchase goods from a registered dealer at the time government issued form “D” to seller. (For saving tax) (N.B:- Form “D” is cannot be issued in case of sale to government on 1-4-2007).