A grocery store manager must decide how to best present a limited supply of milk and cookies to its customers. Milk can be sold by itself for a profit of $1.50 per gallon. Cookies can likewise be sold at a profit of $2.50 per dozen. To increase appeal to customers, one gallon of milk and a dozen cookies can be packaged together and sold for a profit of $3.00 per bundle. The manager has at most 100 gallons of milk and 150 dozen cookies to make available each day. The manager has decided to stock at least 75 individual gallons of milk per day (excluding milk bundled with cookies). Demand for individual packages of cookies is at most 140 dozen per day (excluding cookies bundled with milk). The manager wishes to determine how much of each product to stock each day. The manager's problem falls within which classification?

a. Resource-allocation

b. Cost-benefit-trade-off

c. Mixed problems

d.Transportation problems

e. Assignment problems