The number of hours of sunlight in a day of a leap year, in part of Ontario, can be modelled by a sinusoidal function with a minimum of 8.9 on the 356th day of the year (December 21st), and a maximum of 15.4 on the 173rd day of the year (June 21st).

a. Find a sinusoidal function that models this relationship. [5 marks]

b. What days (on the calendar) are the closest to 14 hours in length? [4 marks]

c. How long is the 218th day of a leap year? [1 mark]