A bridge is in the form of a semi-circle of radius 40m. The greatest speed with which a motor cycle can cross the bridge without leaving the ground at the highest point is \[\left( g=10\text{ }m{{s}^{-2}} \right)\] (frictional force is negligibly small)

• A. \[40\text{ }m{{s}^{-1}}\]
• B. \[20\text{ }m{{s}^{-1}}\]
• C. \[30\text{ }m{{s}^{-1}}\]
• D. \[\text{15 }m{{s}^{-1}}\]