According to the case (p. 4), the cost of generating electricity through solar power had changed from 1976 to 2010. Over that time, producers had learned by doing and had benefited from economies of scale. What effect did this knowledge and growth have on the cost of solar? Question 9 options: a) Increased the cost from $0.15/kWh to $2.00/kWh b) Reduced the cost from $2.00/kWh to approximately $0.15 - $0.35/kWh c) Reduced the cost of solar to a level below the cost of either natural gas or coal d) Left the cost of solar power unchanged over that 30+ year period