Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect ?

Question

( A ) Cerium (IV) acts as an oxidizing agent
( B ) The +3 oxidation state of cerium is more stable than the +4 oxidation state
( C ) The common oxidation states of cerium are +3 and +4
( D ) The +4 oxidation state of cerium is not known in solutions