Wikipedia states that all propositional logic statements can be transformed into CNF.
However, I'm not so sure how we can further simplify $(A \vee B) \wedge (C \vee D)$?
Or if this is CNF, why is it in CNF? To quote wikipedia:
... it is a conjunction of one or more clauses, where a clause is a disjunction of literals; otherwise put, it is a product of sums or an AND of ORs ...
$(A \vee B) \wedge (C \vee D)$ is an AND of two OR's: $A \vee B$ and $ C \vee D$
Moreover, both OR's are disjunctions of literals: $A, B, C,$ and $D$ are all atomic statements, which are all literals.
So, this statement is in CNF