Answer:
1 month.
Step-by-step explanation:
When reading a graph, the most important thing is knowing what the axes are. Here, the horizontal x-axis is months, and the vertical y-axis is the number of books read. Those are our 2 variables.
Now, a line on a graph shows the relationship between those 2 variables. At any given point on the line, it'll have an output value of y (books read) for whatever input value of x.
The question gives you the value on the y-axis (books read), so all you need to do is find the value of x that corresponds to that point on the line. I marked that point on the line in the attached image. Look directly below that point on the line, and you can see that 1 month corresponds to 4 books read.
