The Number of Private Donations Received by Nongovernment Disaster Relief

Multiple Choice

The number of private donations received by nongovernment disaster relief organizations can be modeled as thousand donations where x is the number of hours since a major disaster has struck. At what time is the rate of change of donations zero?
Round to the nearest thousandth.

A) 12.346 hours
B) 0.111 hours
C) 1.111 hours
D) 0.992 hours
E) 11.111 hours