At the isoelectric point, amino acids are present as

Options

A. `H_(2)N-CHR-CO OH`
B. `H_(3)overset(+)(N)-CHR-CO OH`
C. `NH_(2)-CHR-CO O^(-)`
D. `H_(3)N^(+) CHRCO O^(-)`

Answer

D

Explanation

See isoelectric point of `alpha`-amino acids.