The correct graph would be the third option.
This is because we can rearrange the equation 2x + y = 4 into the form y = mx + c by subtracting 2x, giving us y = -2x + 4.
This then tells us that the y-intercept must be at 4, and the slope must be -2. The first option and the third option are the only graphs with an intercept at 4, but the first option has a positive slope and the third option has a negative slope, so that is the answer.
I hope this helps!