Which of the following equation is true for the hyperbola, where P is on the hyperbola curve, F1, F2 are the two fixed points, the foci, and a is the distance from the vertices of the hyperbola to its center.

Which of the following equation is true for the hyperbola, where P is

1.	Which of the following equation is true for the hyperbola, where P is on the hyperbola curve, F1, F2 are the two fixed points, the foci, and a is the distance from the vertices of the hyperbola to its center.
A.	PF1 – PF2 = a
B.	\|\|PF2 \|-\|PF1\|\| = 2a
C.	\|PF1 – PF2 \| = 2a
D.	\|PF2 – PF1 \| = 2a
Answer» C.