In an experiment to determine the focal length (f) of a concave mirror by the u–v method, a student places the object
pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted image from a
distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the
right of the object pin. Then,
(A) x < f (B) f < x < 2f
(C) x = 2f (D) x > 2f