(1) $\int \dfrac {1+x}{1+x^{2}}dx= \underline { \quad \quad \quad }$.
(2) $\int \dfrac {x}{(2x+3)^{2}}dx= \underline { \quad \quad \quad }$.
(3) $\int \dfrac {dx}{x^{2}+2x+5}= \underline { \quad \quad \quad }$.
$\text{A.}$
$\text{B.}$
$\text{C.}$
$\text{D.}$