52. The figure shows the configuration of a beam-expander (5x) formed by two positive lenses with focal lengthes f1 and f2. The distance between two lens is 12 cm. Wi and Wf denote the input and output laser beam diameters, respectively. What is the laser focal point in the system?(A) 2.0 cm away from the input lens (B) 4.0 cm away from the input lens (C) 6.0 cm away from the input lens (D) 8.0 cm away from the input lens (E) 10.0 cm away from the input lens