An airline records data on several variables for each of its flights: model of plane, amount of fuel used, time in flight, number of passengers, and whether the flight arrived on time. The number and type of variables recorded are
a. 1 categorical, 4 quantitative (1 discrete, 3 continuous)
b. 1 categorical, 4 quantitative (2 discrete, 2 continuous)
c. 2 categorical, 3 quantitative (1 discrete, 2 continuous)
d. 2 categorical, 3 quantitative (2 discrete, 1 continuous)
e. 3 categorical, 2 quantitative (1 discrete, 1 continuous)