Which statement about phrase structure rules is false?

(A) Generalization I states that every XP has one and only one head.

(B) Generalization I is violated by a PSR such as XP XX, where X is a head.

(C) Generalization II states that the only non-phrasal element in an XP is X.

(D) Generalization II is violated by a PSR such as XP XX, where X is a head.