A cup of coffee cools according to a temperature function T(t), measured in degrees Celsius, where t is the number of minutes after brewing. At t=8, the derivative satisfies T′(8)=−1.2 (units °C/min). Which of the following best interprets this value?
a) At 8 minutes, the coffee’s temperature is increasing at approximately 1.2∘C per minute.
b) At 8 minutes, the coffee’s temperature is decreasing at approximately 1.2∘C per minute.
c) At 8 minutes, the coffee’s temperature is decreasing at approximately 1.2 minutes per degree Celsius.
d) At 8 minutes, the coffee’s temperature is 1.2∘C.