Correct Answer: Fourth OptionThe total cost is the sum of cost of Ballet Classes for kids and cost of Ballet classes for adults.
For Kids:The cost is $3200 and is increases at a rate of 2% every year. So the cost after x years can be expressed as:
For adults:The cost is $4800 and is increases at a rate of 2.7% every year. So the cost after x years can be expressed as:

Total cost is the sum of these two costs. So,
Therefore, Fourth option is the correct answer.