The Daily Consumption C (In Gallons) of Diesel Fuel on a Farm

Multiple Choice

The daily consumption C (in gallons) of diesel fuel on a farm is modeled by
$C = 30.4 + 21.6 \sin \left( \frac { 2 \pi t } { 365 } + 10.2 \right)$ ,

Where t is the time (in days) , with t = 1 corresponding to January 1.
What is the average daily fuel consumption?

A) 365 gal.
B) 21.6 gal.
C) 30 gal.
D) 10.2 gal.
E) 30.4 gal.