The best way to increase the juiciness of meat and improve its flavor, texture, and aroma from the given options is:
C) Let it rest after it has cooked, but before it's sliced.
Letting meat rest allows the juices to redistribute throughout the meat, resulting in a juicier and more flavorful bite. While the other options may enhance flavor or texture in certain ways, resting is particularly effective at maintaining and enhancing the juiciness of cooked meat.