A Parasitic Protist of Mammalians Contains a Plastid That Is

A parasitic protist of mammalians contains a plastid that is necessary for the synthesis of at least one critical compound. How could this information be used in combatting this protist?

A) The plastid can be specifically targeted by a drug, thus killing the parasite without harming the host.
B) The host could be treated with a protisticide.
C) Plastids are not normally found in protists, therefore they are particularly susceptible to chemical interference.
D) The premise of the question is factually incorrect - protists cannot contains plastids.
E) Plastids do not have plastid-specific functions, therefore are not able to be manipulated to combat the host.