Wind turbines are increasingly used to produce renewable electricity. Some of the largest ones can reach over 140 metres tall. The height of the edge of a windmill blade is modelled by the function hm = acosb (E C}) +d. A true statement about the funcb'on could be Select one: D a. the amplitude is equal to the maximum height divided by 2. O b. the height must be at its maximum when t = 0 if C = 0. O c. the b -va|ue is equal to 2T: divided by the number of revolutions per minute. 0 d. the dvalue can be found by averaging the maximum and minimum heights