Which of the following statements about hormone synthesis is NOT correct?

A)Progesterone can be a precursor of cortisol.
B)Progesterone is a precursor of mineralocorticoid and glucocorticoid hormones.
C)Pregnenolone is a precursor for all steroid hormones.
D)Tryptophan is a precursor for thyroid hormones.
E)Peptide hormones are polymers of amino acids.