A new smart electricity meter has been designed with two components to the cost of electricity: . Whenever any electricity is being provided, there is a service charge rate of $10 per hour. . Additionally, the cost of electricity depends continuously on the rate it is consumed: if the consumption rate is R units of electricity per minute, then the cost per unit is $18 R^2. How long does it take to consume 10 units of electricity as cheaply as possible? Pick ONE option O 6 minutes 10 minutes K 1 hour O 2 hours