A power line is coupled capacitively through various parasitic capacitances to a shielded signal line as shown in the figure. The conductive shield is grounded solidly at one end. Assume that the length of the signal wire extending beyond the shield, and the shield resistance are negligible. The magnitude of the noise voltage coupled to the signal line is
- directly proportional to $C_{1G}$
- inversely proportional to the power line frequency
- inversely proportional to $C_{1S}$
- Zero