A car is negotiating a curved road of radius R. The road is banked at an angle\[\theta \]. The coefficient of friction between the tyres of the car and the road is\[{{\mu }_{s}}\]. The maximum safe velocity on this road is:

• A. \[\sqrt{g{{R}^{2}}\frac{{{\mu }_{s}}+\tan \theta }{1-{{\mu }_{s}}\tan \theta }}\]
• B. \[\sqrt{gR\frac{{{\mu }_{s}}+\tan \theta }{1-{{\mu }_{s}}\tan \theta }}\]
• C. \[\sqrt{\frac{g}{R}\frac{{{\mu }_{s}}+\tan \theta }{1-{{\mu }_{s}}\tan \theta }}\]
• D. \[\sqrt{\frac{g}{{{R}^{2}}}\frac{{{\mu }_{s}}+\tan \theta }{1-{{\mu }_{s}}\tan \theta }}\]