The average daily temperature, t, in degrees Fahrenheit for a city as a function of the month of the year, m, can be modeled by the equation graphed below, where m=0 represents January 1, m=1 represents February 1, m=2 represents march 1, and so on. If the equation is t=acos(pi/6(m+1))+k, what are the values of a and k a=-60; k = 20 a=-50; k=30 a=-30; k=50 a=-20; k=60