A

- Hướng dẫn giải

Ta có: \(I=\lim \left[ n\left( \sqrt{{{n}^{2}}+3}-\sqrt{{{n}^{2}}+2} \right) \right]\)\(=\lim \,\frac{n}{\sqrt{{{n}^{2}}+3}+\sqrt{{{n}^{2}}+2}}\)\(=\lim \,\frac{1}{\sqrt{1+\frac{3}{{{n}^{2}}}}+\sqrt{1+\frac{2}{{{n}^{2}}}}}=\frac{1}{2}\)