The cost, c(x), for a taxi ride is given by c(x) = 2x + 4.00, where x is the number of minutes. what does the slope mean for this situation
a. the taxi ride costs a total of $4.00
b. the taxi ride costs $2.00 per trip.
c. the rate of change of the cost of the taxi ride is $2.00 per minute.
d. the rate of change of the cost of the taxi ride is $4.00 per minute.

As m is a constant that is applied to x, it has to have something to do with minutes, eliminating A and B. As the constant is 2, it has to have something to with 2, eliminating D, meaning your answer is C. This is because a slope is the rate of change of y in relation to x, so it would be rate of change of y is a (a being your constant, in this case 2) per x. With your case, y is cost and x is minutes, leading to answer choice C.