A bicycle has pedal rods of length `16 cm` connected to sprocketed disc of radius `10 cm`. The bicycle wheels are `70 cm` in diameter and the chain runs over a gear of radius `4cm`. The speed of the cycle is constant and the cyclist applies `100 N` for, that is always perpendicular to the pedal rod, as shown in figure. Assume tension in the lower part of chain is negligible. The cyclist is peddling at a constant rate of two revolutions per second. Assume that the force applied by other foot is zero when one foot is exerting `100 N` force. Neglect friction within cycle parts and the rolling friction.
The tension in the upper portion of the chain is equal to
A. `100N`
B. `120N`
C. `160N`
D. `240N`