The water level of a certain body of water is changing at a rate of W(t) == cos inches per hour, where t represents hours since 12 a.m. Part A: Using correct units, explain the meaning of 10W(t)dt in terms of the context of this problem. Part B: Write the integral that represents the number of inches that the water level changes from 7 p.m. to midnight. Part C: Use your calculator to evaluate your integral from Part B. Explain the meaning of the answer in terms of the context. Part D: What is the average hourly number of inches that the water level changes for this lake in one day?