1.A butterfly spread is the purchase of one call at exercise price X₁, the sale of two calls at exercise price X₂, and the purchase of one call at exercise price X₃. X₁ is less than X₂, and X₂ is less than X₃ by equal amounts (i.e., X₂ X₁ = X₃ X₂), and all calls have the same expiration date. If X₁ = $10, X₂ = $15, X₃= $20, what is the minimum and maximum payoff of this strategy?

	A.	Minimum: 0; Maximum: $5
	B.	Minimum: 0; Maximum: $10
	C.	Minimum: 0; Maximum: $15
	D.	Minimum: unlimited; Maximum: $5
	E.	Minimum: unlimited; Maximum: unlimited.