We want to find the slope of this function first to help us get our answer.
The slope of a function can be found with the following formula:

Take any two points from the table to plug into the equation. We'll use (1,2) and (4,8):

The slope of our function will be 2.
All of the answers are in slope-intercept form. Slope-intercept form uses the following formula:

m is the slope, and b is the y-intercept of the equation.
We know that our slope is 2. The only answer with a slope of 2 is y = 2x.
The answer is
D. y = 2x.