Concept:Use the difference of two squares and substitution to reduce the system to simple linear equations.Explanation:From x+y=2, note that x2−y2=(x+y)(x−y).Substitute x+y=2 into x2−y2=4.Then 2(x−y)=4, so x−y=2.Now solve the pair: x+y=2 and x−y=2.Add the equations: 2x=4, so x=2.Substitute x=2 into x+y=2 to get y=0.Answer:x=2, y=0.This matches option C.