Which of the following are the example of double salt? A. \(\mathrm{FeSO}_4 .\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4 …

Which of the following are the example of double salt?
A. \(\mathrm{FeSO}_4 .\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4 .6 \mathrm{H}_2 \mathrm{O}\)
B. \(\mathrm{CuSO}_4 .4 \mathrm{NH}_3 \cdot \mathrm{H}_2 \mathrm{O}\)
C. \(\mathrm{K}_2 \mathrm{SO}_4 \cdot \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3 \cdot 24 \mathrm{H}_2 \mathrm{O}\)
D. \(\mathrm{Fe}(\mathrm{CN})_2, 4 \mathrm{KCN}\)
Choose the correct answer
[JEE Main 2023, 1 Feb (Shift 1)]