Which function is represented by the graph ?

The answer is a. This is because the +1 is where the line intercepts on the y-axis. the -2x is the rise over run and since it is an absolute x, it can go either way, so it has two lines.
We are given graph of an absolute function:
The standard form of an absolute function is :
y=a| x−h |+k, where (h,k) is the vertex of the graph.
For the given graph of absolute function, we have vertex at (0,1).
And because it's open down the value of a should be a negative number.
|a| >1, it would vertically stretch by a factor of 2.