A skater of mass 45 kg is travelling in a circle of radius 4 m at a constant speed. What is their speed if the horizontal force they exert on the ground to prevent them from slipping is 1125 N

A 10 m/s
B. 20 m/s
C. 5 m/s
D. 100 m/s
E. The speed cannot be determined since we don't know
the time interval.