What is the best practice to prevent a user from discounting a specific Product Type?

What is the best practice to prevent a user from discounting a specific Product Type?
A . Customizing cart UI template section making discount cell read-only for the product type items.
B . Adding a custom script that resets the product Type items to zero on every Quote change.
C . Removing visibility of the discount column for the user Types in Quote Layout Permissions setup.
D . Setting discount percent minimum and maximum values to zero for the product Type in Discounts/multipliers setup.

Answer: C