13. The amount of daylight in a town can be modelled by the sinusoidal function d(t) = 4.37 cos 0.017t + 12.52 where d(t) represents the hours of daylight and t represents the number of days since June 20, 2012. How many hours of daylight should be expected on June 20, 2013? a) 16.80 hr b) 16.88 hr c) 16.84 hr d) 16.92 hr