Plz someone i don't understand the fraction part

First of all the answer is C:

The equation for linear equations (something that goes up at a constant rate) is y= mx + c
y= 1/3x + 5 is the answer because:

m = the difference, between each y value , because the x goes up 6 at a time, and the difference is 2. The m value is 2/6, or simplified to 1/3

c = a value to make it all work, so when x = 0 , y = 5, so we know no matter what x equals, there is a 5, this is what c equals. C = 5