Choose the most accurate sentence below.
a. Using a function as a model for a real-world phenomenon means we usually have to impose artificial restrictions on the domain.
b. Using a function as a model for a real-world phenomenon is impossible and is never done.
c. Using a function as a model for a real-world phenomenon is theoretically possible but practially useless.
d. Using a function as a model for a real-world phenomenon means we never have to impose artificial restrictions on the domain.
e. Using a function as a model for a real-world phenomenon means we always have to impose artificial restrictions on the range.