To find the average price per person excluding the gratuity, we need to subtract the gratuity amount from the total price and then divide it by the number of people.
The total price including the gratuity is $207, which is equal to 100% + 15% = 115% of the average price per person. So, the average price per person would be $207 / 115% = $180.
To find the average price per person excluding the gratuity, we divide $180 by 15 people:
Average price per person = $180 / 15 = $12
Therefore, the answer is (B) $12.