A Child Swings a 0

A child swings a 0.38 kg ball in a circle on a string that is 1.3 m long.If the ball makes 1.2 rev/s,what is the magnitude of the ball's angular momentum?

A) 4.8 kg∙m²/s
B) 0.8 kg∙m²/s
C) 3.8 kg∙m²/s
D) 5.3 kg∙m²/s