Amino acid score of animal foods –: (A) 40–50, (B) 50–60, (C) 70–80, (D) 90–100
Answer is C. Amino acid score (chemical score)

It is used for qualitative assessment of protein.
It is a measure of the concentration of each essential amino acid in the test protein expressed as a percentage of that amino acid in reference protein (egg protein).

Amino acid score = No. of mg of one amino acid per gm of protein / No. of mg of same amino acid per gm of egg protein x 100

The amino acid score is between 50 and 60 for starches and 70-80 for animal foods.