"There Is One and Only One President of the United

Multiple Choice

"There is one and only one President of the United States " can best be symbolized (Pxy: x is a president of y; u: the United States) as

A) ($x) (Pxu • (y) (Pyu → y = x) ) .
B) (x) (y) (Pxu → ~Pyu) .
C) ($x) Pxu • (x) (y) ((Pxu • Pyu) → x = y) .
D) (x) (Pxu • (y) (~y = x → ~Pyu) ) .