Which pair (x,y)(x, y)(x,y) satisfies 3x+y=73x + y = 73x+y=7 for non-negative integers?
(1,4)(1, 4)(1,4)
(2,2)(2, 2)(2,2)
(3,−2)(3, -2)(3,−2)
(0,8)(0, 8)(0,8)