On a given workday, the rate, in tons per hour, at which unprocessee ore arrives at a refinery is modeled by O (t) = 20 + 10 cos (t^2÷25) where t is measured in hours and 0 <= t <= 10. At the beginning of the workday, t = 0, the refinery has 100 tons of unprocessed ore. During the hours of operation, the refinery processes ore at a constant rate of 25 tons per hour.

(A) Find O^1(4). Usng correct units, interpret your answer in the context of the problem.
(B) How much total ore has been processed by the refinery after the plant has been open for 3 hours.
(C) Is the amount of unprocessed ore at the refinery increasing or decreasing at time t = 4 hours? Show the work that leads to your answer
(D) Determine the time at which the total rate of ore at the refinery is neither increasing nor decreasing? Justify your answer