Answer:
It's D)
C is incorrect because the constant is + 1, not - 8
A is incorrect because the f doesn't go up by 2 for every x value
B is incorrect because 2/3 * 2 would be 4/3 which is 1 1/3, which is wrong because g goes up by 2 every x.
D is correct because f goes up by 1/3, and the y-intercept is 1 (Where the line meets when the x-axis is 0) and 1/3 * 6x is 6x/3 which is 2x, then add the y-intercept to the equation, which should be 2x + 1