There are a few ways you could do this problem. You could either notice that, by creating point on a graph, that there is a point (0,3). (0,3) suggests there is a y-intercept, thus meaning only y=x+3 would be the correct answer.
You could also solve by creating points of your own, solving for slope, and then solving for the y-intercept.
Using (-3,0) and (-2, 1), solve the slope of the graph by using the slope formula (y2-y1)/(x2-x1).
Let (-3,0) be x1 and y1 respectively and let (-2,1) be x2 and y2 respectively.
(1-0)/(-2-(-3)) = 1/1 = 1
The slope is 1.
Now, you have y = 1x + b
Solve for "b" by selecting a coordinate from the graph and applying that coordinate in place of "y" and "x." Let's use (-3,0).
0 = 1(-3) + b
Solving gets you b = 3.
y = 1x + 3
y=x + 3
Hope this helps!