Emilio owns a bakery. The number of boxes of cookies he has left on a Monday is represented by the function x + y = 42, where y is the number of boxes of cookies remaining in the bakery and x is the number of hours since he opened the bakery. How many boxes did he have at the start of business on Monday? (Note: x ≥ 0, y ≥ 0, and y takes only integer values.) A. 46 B. 40 C. 42 D. 38
