The left part of the graph is parabolic as it looks curvy and we know this for sure as all of the f(x) or y = x^2 is the same for the top part of each answer choice when x<1.  
We need to analyze the linear part of the function.   Below please find the line extended.
Since the equation of a line is y = mx + b where m is slope and b is y-intercept, we can find b by looking at the line below.  
It crosses the y-axis at 1/2 so look at the answer choices and find the equation with a b of 1/2.
That’s it!! 2 points 🙂