Suppose a carpenter produces chairs and tables. Each table costs $75 to make, while production costs for each chair are $50. The selling price for each table is $125, while each chair sells for $75. Let x equal the number of tables sold and y equal the number of chairs sold. An algebraic formulation of the profit function is:

a.max(50x + 25y)

b.max(125x + 75y)

c.min(75x + 50y)

d.max(75x + 50y)