Hong hikes at least 1 hour but not more than 4 hours. She hikes at an average rate of 2.7 mph. The function f(t)=2.7t represents the distance she hikes in t hours.
What is the practical range of the function?
a) all real numbers from 1 to 4, inclusive
b) all real numbers
c) all real numbers from 2.7 to 10.8, inclusive
d) all multiples of 2.7 between 2.7 and 10.8, inclusive