The anticancer drug methotrexate inhibits nucleotide synthesis. Which of the subsequent explains why it also inhibits the synthesis of histidine and methionine?

a. The synthetic pathways for these amino acids need tetrahydrofolate for group transfer reactions

b. These amino acids are derivatives of the nucleotides UTP and GTP

c. Methotrexate as well inhibits the precursors for these amino acids

d. Without the synthesis of nucleotides there isn't sufficient energy for the synthesis of the amino acids