Answer: The correct option is, It is a line joining the points whose x and y coordinates add up to 4.
Step-by-step explanation:
The given equation is,
when we take x = 1 then
when we take x = 2 then
From this we conclude that the sum of 'x' and 'y' coordinates is always equal to 4.
Hence, the correct answer is, It is a line joining the points whose x and y coordinates add up to 4.