Give the structure of the compounds in the following reactions
`CH_(2)=CH-CH_(2)OH overset(CrO_(3).2C_(5)H_(5)N)underset(CH_(2)Cl_(2))rarr[A]underset(H^(+))overset(CH_(3)OH)rarrunderset(C_(5)H_(10)O_(2))([B])underset(("Cold,dil"))overset(KMnO_(4)//OH^(-))rarrunderset((C_(5)H_(12)O_(4)))([C])overset(H_(3)O^(+))rarrunderset((C_(3)H_(6)O_(3)))([D])`