Methotrexate leucovorin 5 fluorouracil hydroxyurea

Which of the following statements regarding antimetabolite agents is least accurate?

1: 5-Fluorouracil inhibits thymidylate synthase
2: Hydroxyurea inhibits ribonucleotide reductase
3: Methotrexate inhibits dihydrofolate reductase
4: Methotrexate inhibits ribonucleotide reductase