Answer:
Option C.
Step-by-step explanation:
If a line passes through two points
and
, then the rate of change is

From the given graph it is clear that the line passes through the points (0,20) and (10,50). So, the slope of the lien is

The slope of two parallel lines are same. So, the slope of parallel line is 3.
The point slope form of a line is

The slope of parallel line is 3 and it passes through the point (4,15). So, the equation of parallel line is

Using distributive property

Add 15 on both sides.


The required equation is y=3x+3. Therefore, the correct option is C.