Which of the following statement$(s)$ is/are true?
$(i)$ All amino acids contain one chiral centre.
$(ii)$ Some amino acids contain one, while some contain more chiral centres or even no chiral centre.
$(iii)$ All amino acids in proteins have $L$-configuration.
$(iv)$ All amino acids found in proteins have $1^{\circ}$ amino group.

• A
  $(ii), (iii)$ and $(iv)$
• B
  $(ii)$ and $(iii)$
• C
  $(i), (iii)$ and $(iv)$
• D
  $(i)$ and $(iv)$