According to Bohr's theory the radius of electron in an orbit described by principal quantum number n and atomic number Z is proportional to [CPMT 1988]

• A.   \[{{Z}^{2}}{{n}^{2}}\]        
• B.   \[\frac{{{Z}^{2}}}{{{n}^{2}}}\]
• C.   \[\frac{{{Z}^{2}}}{n}\]      
• D.   \[\frac{{{n}^{2}}}{Z}\]