Geometry question, help!

Point P lies on line m. Point P is also included in distinct planes Q, R, S, and T. At most, how many of these planes could be perpendicular to line m

If you could explain how you answered this, that would be great since I'm having a little trouble understanding this. Thanks

A plane can be defined as being perpendicular to a line and being a certain distance along that line. For example, the x-y plane (the plane made by the x and y axes) is perpendicular to the z axis at z=0.

Only one plane could be perpendicular to m. If a second plane was perpendicular to m at p, it would no long be distinct from the first.