A dietitian needs to purchase food for patients. She can purchase an ounce of chicken for $0.25 and an ounce of potatoes for $0.03. Let x = the number of ounces of chicken and y = the number of ounces of potatoes purchased per patient. Write the objective function that describes the total cost per patient per meal.

a. z = 3y + 25y

b. z = 0.25x + 0.03y

c. z = 25x + 3y

d. z = 0.03x + 0.25y