Which one of the following is correct?

Options

A. Of the `d^(4)` species, `Cr^(2+)` is strogly reducing while `Mn^(3+)` is strongly oxidising
B. `Co^(2+)` is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised
C. The `d^(1)` configuration is very unstable in ions
D. Sc readily form stable oxide of the type MO

Answer

A, B, C