Answer:
I think 2600 passwords are possible
Step-by-step explanation:
Rotation by -90° about the origin is the transformation ...
(x, y) ⇒ (y, -x)
So, your pre-image points are ...
A'(6, 3) ⇒ A(3, -6)
B'(-2, 1) ⇒ B(1, 2)
C'(1, 7) ⇒ C(7, -1)
your answer is C