Suppose that the y-axis represents total cost and the x-axis represents the unit quantity purchased. which price option can be represented by a linear equation of the form y = ax + b?

a) unit price discounts occur after each 100 purchased.

b) there is a shortage of this item, and to prevent hoarding, the price per unit increases with the quantity purchased.

c) the units are only sold in lots of 100. the buyer pays for the number of whole or fractional lots.

d) the unit cost remains the same regardless of the number of units purchased.