Why does limiting access to over-the-counter cold medicines like Sudafed help reduce methamphetamine production?

Why does limiting access to over-the-counter cold medicines like Sudafed help reduce methamphetamine production?

A) Medicines like Sudafed contain methamphetamine.

B) Medicines like Sudafed can be mixed with cocaine to produce methamphetamine.

C) Medicines like Sudafed can be traded for methamphetamine.

D) Medicines like Sudafed contain pseudoephedrine.