Provide an Appropriate Response $r ( t ) = t ^ { 3 } i + t ^ { 2 } j$

Multiple Choice

Provide an appropriate response.
-The following equations each describe the motion of a particle. For which path is the particle's speed constant?
(1) $r ( t ) = t ^ { 3 } i + t ^ { 2 } j$
(2) $r ( t ) = \cos ( 8 t ) i + \sin ( 6 t ) j$
(3) $r ( t ) = t i + t j$
(4) $r ( t ) = \cos \left( - 5 t ^ { 2 } \right) \mathbf { i } + \sin \left( - 5 t ^ { 2 } \right) \mathbf { j }$

A) Path (4) and Path (2)
B) Path (1)
C) Path (2) and Path (3)
D) Path (3)