Which Drug Reduces the Supply of 5,10-Methylene-Tetrahydrofolate and Thereby Prevents

Which drug reduces the supply of 5,10-methylene-tetrahydrofolate and thereby prevents formation of deoxythymidine monophosphate?

A) mercaptopurine
B) cytarabine
C) fluorouracil
D) hydroxyurea
E) methotrexate