Tyrosine is a nonessential amino acid. What does this mean?

a. Tyrosine is not needed or used by the body's cells.
b. Tyrosine must be regularly consumed or a deficiency will develop.
c. Consuming tyrosine is hazardous to health.
d. The body can synthesize tyrosine from another amino acid.
e. Tyrosine is indispensable

d. The body can synthesize tyrosine from another amino acid.