Which graph represents the system of inequalities Y

In this problem, volume is computed:

volume = ∫(flow rate)·dt 

.. = ∫[0, t] (3/10)*sin(2πt/7)·dt

= (3 / 10)*(7 /(2 π))*(-cos (2 π t/7)+1) 

= (-21 / (20 π))*(cos (2 π t /7) - 1)

Volume is equal to 21 sin^2 (pit/7) / 10pi is the inhaled air in the lungs at time t