Q: The following blue paths are type LSL Dubins paths, starting from the origin and ending tangential to the red circle. Which is shorter?

A: The path B is shorter. When the final position is constrained to lie on a circle, and the final heading is tangential to the circle, the shortest of any CSC path occurs when the heading direction of the straight line segment (middle segment in CSC) passes through the center of the circle.

Refer to this paper for proof.