The graph is
function because it is symmetrical about the

Functions can be symmetrical about the y-axis, which means that if we reflect their graph about the y-axis we will get the same graph. ... These are two types of symmetry we call even and odd functions.

Step-by-step explanation:

The correct choice is B.

When you have a vertical line in a probability statement, it is referring to the fact that the second event has already happened.

Imagine, drawing marbles from a bag of blue and red marbles. You could write a probability statement in which you asked, "What is the probability of drawing a red marble given that you just drew a blue marble?" 

In this case, you would use a vertical line separating the two events.