[单选题]
The maximum speed around a level curve is 30.0 km/h. What is the maximum 1dp0+ awug3e jypp8-whpm6z ( speedkgu )uqej fb3 fr6.,sr)*tro2 around a curve with twice the radius? (Assume all other 2j3b 6fe qrr., s*g)uko)f turfactors remain unchanged.)
A. 42.4 km/h
B. 45.0 km/h
C. 60.0 km/h
D. 120 km/h
