Final answer:
The correct expression representing the money raised by selling custom hats is 6n - 50, which accounts for both the profit per hat and the advertising costs.
Step-by-step explanation:
The expression that represents the money raised by the parent volunteer group through the sale of custom hats is found by calculating the net profit per hat and then accounting for the advertising cost. The profit for each hat is the difference between the selling price and the cost to make the hat. So, profit per hat is calculated as $12 (selling price) - $6 (cost) = $6. If n represents the number of hats sold, the total profit from the hats is 6n. Then, subtracting the advertising cost of $50 gives us the final expression for the money raised: (12 - 6)n - 50, or 6n - 50.