The logistics/operations manager of a mail order house purchases two products for resale: king beds (K) and queen beds (Q). Each king bed costs $500 and requires 100 cubic feet of storage space, and each queen bed costs $300 and requires 90 cubic feet of storage space. The manager has $75,000 to invest in beds this week, and her warehouse has 18,000 cubic feet available for storage. Profit for each king bed is $300 and for each queen bed is $150. Which of the following is not a feasible purchase combination?

a. 100K - 90Q <= 18,000
b. 90K + 100Q <= 18,000
c. 300K + 90Q <= 18,000
s. 500K + 100Q <= 18,000
e. 100K + 90Q <= 18,000