Hi there!
When the slopes of two perpendicular lines are multiplied the outcome will be -1.
The slope is the number that is positioned in front of the variable x in the formula. In this case the slope of the given line is -2/5.
Let's call the slope of the perpendicular line m and take into account the given data of the question and my earlier explanation. We then find the following:

Divide both sides by - 2/5.

The answer is B.
~ Hope this helps you!