An insulin infusion is running at 5 mL/hr. The infusion is made up of 30 units of insulin in 50 mL sodium chloride 0.9%. The patient weighs 30 kg. What rate is being delivered in units /kg/hr ?

A. 1 units /kg/hr
B. 0.5 units /kg/hr
C. 0.1 units /kg/hr
D. 0.2 units /kg/hr