A Boy on a Bicycle Rides in a Circle of Radius

Multiple Choice

A boy on a bicycle rides in a circle of radius $r_{0}$ at speed $v_{0}$ . If the boy rides at the same radius $r_{0}$ , by what approximate factor must he change his speed in order to triple his radial acceleration?

A) 9.0
B) 3.0
C) 0.33
D) 1.7
E) 0.58
F) 0.11