A particle is projected from point \[O\] with velocity \[u\] in a direction making an angle \[\alpha \] with the horizontal. At any instant its position is at point \[p\] at right angles to the initial direction of projection, Its velocity at point \[p\] is

• A. \[u\tan \alpha \]            
• B. \[u\cot \alpha \]
• C. \[u\operatorname{cosec}\alpha \]
• D. \[u\sec \alpha \]