Based on the scenario you've described, where the price of dark chocolate has increased dramatically yet the quantity consumed has also risen due to new information about its health benefits, the most appropriate conclusion would be:
Increase in price is because of increase in demand for dark chocolate.
This conclusion aligns with the principle that a rise in demand for a product can lead to an increase in its price, even if the law of demand typically states that higher prices lead to lower quantities demanded. In this case, the positive health news about dark chocolate has shifted the demand curve to the right, leading to both higher demand and higher prices.