$A$ salt '$A$' which gives a green flame with a Bunsen burner,on reaction with dil. $H_2SO_4$ produces gas $(2)$ and white turbidity $(Z)$. The saturated solution of gas $(2)$ on reaction with $H_2S$ gas produces '$Z$'. Then select the $CORRECT$ statement.

• A
  Gas $(2)$ is $CO_2$
• B
  Gas $(2)$ is $SO_2$
• C
  White turbidity $(Z)$ is of elemental sulphur
• D
  Both $(B)$ and $(C)$ are correct