You are supposed to calibrate the voltage signal of the simple pendulum by establishing a relation between the deflection angle c and the voltage signal U. Why do you need the relation of the angle versus voltage? O a. To convert the measured angle 4 into the oscillation period T. O b. To convert the recorded/measured voltage U into the deflection angle o for the measurement of the damped oscillation. O C. To convert the measured voltage U into the oscillation period T." To convert the measured voltage U into the oscillation period T. O d. To convert the recorded/measured time t into the deflection angle 4 for the measurement of damped oscillation