A

Step 1: Understand the setup of the problem with the inextensible strings and how they influence the velocities u and v.
Step 2: Apply the principle of conservation of velocity across the strings. In inextensible systems, any movement in one part affects all parts according to their geometric relations.
Step 3: Derive the relationship between u and v based on the angles or proportions given in the figure, considering velocity components.
Therefore, the value of u in terms of v can be expressed as: u = 2v.