What does a deficiency of Riboflavin (Vitamin B2) lead to?

A deficiency of riboflavin, also known as Vitamin B2, is primarily associated with symptoms of angular stomatitis, cheilosis, and sore throat, which can include swelling in the gums. This vitamin plays a crucial role in energy production and the metabolism of fats, drugs, and steroids. While riboflavin deficiency can lead to some general symptoms affecting the skin and may even influence energy levels, the most characteristic sign is related specifically to oral health, including inflammation and swelling of the mucous membranes in the mouth and gums.

Riboflavin's key functions in maintaining healthy skin and mucous membranes, as well as participating in the cellular processes of other nutrients, further connect its deficiency with oral presentations more so than the other choices. This makes the swelling of the gums a classic sign of riboflavin deficiency, aligning well with the knowledge of its roles in the body.