Which of the following is the best definition of an ordered-pair solution to a two-variable linear equation?

For the equation 2x - y = 4, compute the ordered pairs when x = -1, x = 0, and x = 3, and identify the slope of the line from those points.

Solve the equation 6x + 9y = 15 for y in terms of x.

Given two points observed on a graph, $(2,-1)$ and $(5,8)$, derive the equation of the line in standard form $ax+by=c$ with integer coefficients.

Find x- and y-intercepts for the equation 5x + 2y = 20.