Two linear equations have an infnite number of solutions if and only if they have the same graph. Then, we just need to find the equation of this graph. Since it passes through (0,-4) then the y-intercept is -4. Besides, the slope is 1 since for every unit we move to the right the graph moves one unit up. Then the equation (using the slope-intercept form) is
Then, the first option, y-x=-4 will form a system that has an infinite number of solutions.