15. For any time $t \geq 0$, if the position of a particle in the $x y$-plane is given by $x = t ^ { 2 } + 1$ and $y = \ln ( 2 t + 3 )$, then the acceleration vector is\\
(A) $\left( 2 t , \frac { 2 } { ( 2 t + 3 ) } \right)$\\
(B) $\quad \left( 2 t , \frac { - 4 } { ( 2 t + 3 ) ^ { 2 } } \right)$\\
(C) $\quad \left( 2 , \frac { 4 } { ( 2 t + 3 ) ^ { 2 } } \right)$\\
(D) $\left( 2 , \frac { 2 } { ( 2 t + 3 ) ^ { 2 } } \right)$\\
(E) $\quad \left( 2 , \frac { - 4 } { ( 2 t + 3 ) ^ { 2 } } \right)$\\