A

$\int_0^{+\infty}\dfrac{x}{1+x^2}\,dx$

B

$\int_1^{+\infty}\sin x\,dx$

C

$\int_a^{+\infty}\dfrac1{\sqrt{x}}\,dx$

D

$\int_4^{+\infty}\dfrac1{4-x^2}\,dx$