The motion of a simple pendulum executing S.H.M. is represented by the following equation.\( y = A \sin(\pi t + \phi) \), where time is measured in second. The length of pendulum is:
\( 97.23 \ \text{cm} \)
\( 25.3 \ \text{cm} \)
\( 99.4 \ \text{cm} \)
\( 406.1 \ \text{cm} \)