On March 17, 1981, in Tucson, Arizona, the Temperature in Degrees

On March 17, 1981, in Tucson, Arizona, the temperature in degrees Fahrenheit could be described by the equation $T ( t ) = - 10 \cos \left( \frac { \pi } { 12 } t \right) + 55$ while the relative humidity in percent could be expressed by $H ( t ) = 25 \cos \left( \frac { \pi } { 12 } t \right) + 60$ where t is in hours and t = 0 corresponds to 6 AM. Find the maximum value of the humidity.

A) H = 10%
B) H = 90%
C) H = 35%
D) H = 55%
E) H = 85%