`FeO*Cr_(2)O_(3) underset(O_(2)) overset(Na_(2)CO_(3))to A overset(H_(2)SO_(4))toB overset(KCl)toC`
The hybridisation of compound C and colour of its crystal is
A. `sp^(3)` , orange red
B. `sp^(3)`, yellow
C. `sp^(2)` , orange red
D. `sp^(2)` , yellow