The correct option$(s)$ to distinguish nitrate salts of $Mn^{2+}$ and $Cu^{2+}$ taken separately is (are):
$(A)$ $Mn^{2+}$ shows the characteristic green colour in the flame test
$(B)$ Only $Cu^{2+}$ shows the formation of precipitate by passing $H_2S$ in acidic medium
$(C)$ Only $Mn^{2+}$ shows the formation of precipitate by passing $H_2S$ in faintly basic medium
$(D)$ $Cu^{2+}/Cu$ has higher reduction potential than $Mn^{2+}/Mn$ (measured under similar conditions)

• A
  $A, B$
• B
  $A, C$
• C
  $A, D$
• D
  $B, D$