The correct answer is A.
The load factor of a power station is the ratio of the average load to the maximum demand. It is a measure of how efficiently a power station is being used. A high load factor indicates that the power station is being used close to its maximum capacity, while a low load factor indicates that the power station is being underutilized.
Option B is incorrect because it is the product of the average load and the maximum demand, not the ratio. Option C is incorrect because it is the reciprocal of the load factor. Option D is incorrect because it is the square root of the product of the average load and the maximum demand, not the ratio.