The Common Feature Of $\alpha$ -Substitution and Condensation Reactions of Carbonyl Groups:
A) Involve Two

The common feature of $\alpha$ -substitution and condensation reactions of carbonyl groups:

A) involve two carbonyl partners
B) involve the formation of an enol or enolate ion
C) involve a nucleophile
D) produce a new carbon to carbon bond
E) all of these describe both types of reactions