What is the biconditional statement of the following conditional statement?

"If the product of the slopes of two lines is −1, then the lines are perpendicular."

A If the lines are perpendicular, then the product of the slopes of two lines is −1.
B The product of the slopes of two lines is −1 if and only if the lines are perpendicular.
C If the product of the slopes of two lines is not −1, then the lines are not perpendicular.
D If the two lines are not perpendicular, then the product of the slopes of two lines is not −1.