If\[{{n}_{1}}\],\[{{n}_{2}}\]and \[{{n}_{3}}\] are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by

• A. \[\frac{1}{n}=\frac{1}{{{n}_{1}}}+\frac{1}{{{n}_{2}}}+\frac{1}{{{n}_{3}}}\]
• B. \[\frac{1}{\sqrt{n}}=\frac{1}{\sqrt{{{n}_{1}}}}+\frac{1}{\sqrt{{{n}_{2}}}}+\frac{1}{\sqrt{{{n}_{3}}}}\]
• C. \[\sqrt{n}=\sqrt{{{n}_{1}}}+\sqrt{{{n}_{2}}}+\sqrt{{{n}_{3}}}\]
• D. \[n={{n}_{1}}+{{n}_{2}}+{{n}_{3}}\]