Which of the following amino acids will have a net charge of zero at its $\text{isoelectric point (pI)}$ and what is the approximate $\text{pI}$ value for $\text{Lysine}$ (${\text{pK}}_{a1}=2.18,{\text{pK}}_{a2}=8.95,{\text{pK}}_{a3}=10.53$)?

1. A.All amino acids have a net charge of zero at $\text{pI}$; $\text{pI}$ of $\text{Lysine}$ is $9.74$.
2. B.Only acidic amino acids have a net charge of zero at $\text{pI}$; $\text{pI}$ of $\text{Lysine}$ is $6.37$.
3. C.All amino acids have a net charge of zero at $\text{pI}$; $\text{pI}$ of $\text{Lysine}$ is $5.56$.
4. D.Only basic amino acids have a net charge of zero at $\text{pI}$; $\text{pI}$ of $\text{Lysine}$ is $10.53$.