Let PQ be a diameter of a circle,
     A be a point on line PQ such that P lies between A and Q,
     T be a point on the circle such that line AT is tangent to the circle,
     B be the point on line QT such that line BP is perpendicular to line PQ, and
     C be the point on line PT such that line CQ is perpendicular to line PQ.

Prove that points A, B, and C are collinear.