Hey kmgraju and welcome to the forums.
A B-Spline is an interpolation curve that is a lot more general whereas a bezier curve is a cubic polynomial expression (for each dimension, example curve, surface, volume, etc) that is an approximation curve given control points.
Interpolation curves go through the control points whereas approximation curves don't necessarily go through the points. You'll note that a bezier curve/surface/volume goes through only the end-points and in general is only 'pulled' towards the middle two points and doesn't go through them (like an interpolation curve does).