The Sugar Act primarily enforced existing laws regarding taxes on molasses. It aimed to reduce the previous tax on molasses but made the enforcement of customs duties more stringent and aimed at curbing smuggling. Therefore, the most accurate description from the options provided would be:
It enforced existing laws regarding taxes on molasses.
However, it is important to note that the Sugar Act of 1764 also aimed to increase revenue by tightening regulations and enforcing harsher penalties for smuggling.