If R(t) Is the Position Vector of a Particle in the Plane

Multiple Choice

If r(t) is the position vector of a particle in the plane at time t, find the indicated vector.
-Find the velocity vector. r(t) = (cot t) i + (csc t) j

A) $\mathbf { v } = \left( - \sec ^ { 2 } t \right) \mathbf { i } - ( \tan t \sec t ) \mathbf { j }$
B) $\mathbf { v } = \left( \csc ^ { 2 } \mathrm { t } \right) \mathbf { i } + ( \cot \mathrm { t } \csc \mathrm { t } ) \mathbf { j }$
C) $\mathbf { v } = \left( - \csc ^ { 2 } \mathrm { t } \right) \mathbf { i } - ( \cot \mathrm { t } \csc \mathrm { t } ) \mathbf { j }$
D) $\mathbf { v } = \left( \sec ^ { 2 } \mathrm { t } \right) \mathbf { i } + ( \tan \mathrm { t } \sec \mathrm { t } ) \mathbf { j }$