Cerium `(Z= 58)` is an important nember of the lanthanoids . Which of the following statements about cerium is incorrect ?
A. The +4 oxidation state of cerium is not know in solution.
B. The +3 oxidation state of cerium is more stable than the +4 oxidation state
C. The common oxidation state of cerium are +3 and +4
D. Cerium (IV) acts as an oxidising agent.