Amino acid precursor of lignin

Answer: Option A

Amino acid precursor of lignin is Phenylalanine.
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants.
The biosynthesis begins in the cytosol with the synthesis of glycosylated monolignols from the amino acid phenylalanine. The reactions are shared with the phenylpropanoid pathway.