For what purposes are esters commonly used?

Esters are commonly used for a variety of purposes, the most notable being their role as solvents and their characteristic fruity smells. They are often found in the formulation of paints, coatings, and other products where a solvent is required to dissolve other ingredients and facilitate application.

Additionally, esters naturally occur in many fruits and contribute to their pleasant aromas, making them desirable in food flavorings and fragrances. This dual functionality—serving as both solvents and imparting fruity flavors and scents—is a significant reason why option B is the correct choice among the provided answers.

The other options are too narrow or specific, not capturing the full range of applications of esters. For example, focusing solely on esters being used only as solvents or only in food does not reflect their broader uses in everyday products. Esters indeed serve various roles across industries, showcasing their versatility beyond any single application.