Correct option is (B) 4
\(\because\) \(x=\sqrt{5}+2\)
\(\therefore\) \(\frac1x=\frac1{\sqrt{5}+2}\) \(=\frac{\sqrt{5}-2}{(\sqrt{5}+2)(\sqrt{5}-2)}\)
\(=\frac{\sqrt{5}-2}{5-4}\) \(=\sqrt{5}-2\)
\(\therefore\) \(x-\frac{1}{x}\) \(=(\sqrt{5}+2)-(\sqrt{5}-2)=4\)