Which of the following statements (s) is (are) correct with reference to the ferrous and ferric ions?
(a). `Fe^(3+)` gives brown colour with potassium ferricyanide.
(b). `Fe^(2+)` gives blue precipitate with potassium ferricyanide.
(c). `Fe^(2+)` gives red colour with potassium thiocyanate.
(d). `Fe^(2+)` gives brown colour with ammonium thiocyanate.