The number of minutes of daylight per day for a certain city can be modeled by the function D given by D(t)=160 cos((2pi)/365(t-172)) +729, where t is the day of the year for 1 ≤t≤ 365.
Which of the following best describes the behavior of D(t) on day 150?

A
The number of minutes of daylight per day is increasing at a decreasing rate.
B
The number of minutes of daylight per day is decreasing at a decreasing rate.
C
The number of minutes of daylight per day is increasing at an increasing rate.
D
The number of minutes of daylight per day is decreasing at an increasing rate.