$r(t)$ is the position, $v(t)$ Velocity $,$ and $a(t)$ Acceleration vectors of a particles $($t$-$time$).$ match the definitions $v(t)$ is

A$.dr\frac{t}{d}t$

$a(t)$ is

B$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}v(t)dt$

$r(t)$ is

C$.dv\frac{t}{d}t$

D$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}a(t)dt$