For each variable, determine whether it is best thought of as discrete or continuous.

Variable Discrete Continuous

(a) The actual length of a roll of plastic wrap advertised to be 30

feet long

(b) The body temperature measurement of a participant in a lie-detector test

(c) The number of personal-injury traffic accidents last week on Interstate 65 in Indiana

(d) The fuel efficiency, in miles per gallon, of an American-made car