Let the Position Function of a Particle Be $\mathbf { r } ( t ) = \left\langle t ^ { 2 } , 1 - 2 t , t \right\rangle$

Multiple Choice

Let the position function of a particle be $\mathbf { r } ( t ) = \left\langle t ^ { 2 } , 1 - 2 t , t \right\rangle$ . Find the smallest value of its speed.

A) 0
B) 1
C) $\sqrt { 2 }$
D) $\sqrt { 3 }$
E) 2
F) $\sqrt { 5 }$
G) $\sqrt { 6 }$
H) $\sqrt { 7 }$