Which one of the following is the correct constraint to add if investment 3 and 5 cannot be selected at the same time?

Question 4 options:

	None of the above
	X_3+X_5=1
	X_3+X_5
	X_3+X_5>=1

Spencer Enterprises must choose among a series of new investment alternatives. The potential investment alternatives, the net present value of the future stream of returns, the capital requirements, and the available capital funds over the next three years are sum- marized as follows: Alternative Limited warehouse expansion Extensive warehouse expansion Test market new product Advertising campaign Basic research Purchase new equipment Capital funds available Net Present Value ($) 4,000 6,000 10,500 4,000 8,000 3,000 Capital Requirements ($) Year 1 Year 2 Year 3 3,000 1,000 4,000 2,500 3,500 3,500 6,000 4,000 5,000 2,000 1,500 1,800 5,000 1,000 4,000 1,000 500 900 10,500 7,000 8,750