Final answer:
Leonardo da Vinci's self-portrait is known as 'Leonardo da Vinci's Self-Portrait'. It is neither the Vitruvian Man, Mona Lisa, nor any other titled work, but a separate drawing representing Da Vinci himself.
Step-by-step explanation:
The self-portrait of Leonardo da Vinci is simply known as Leonardo da Vinci's Self-Portrait. It does not share a name with any of his other famous works such as the Vitruvian Man, the Annunciation, the Mona Lisa, or the Salvator Mundi. Among these options, the only work that can be confused for a self-portrait due to speculation is the Mona Lisa, which has led some to theorize about the identity of the sitter, with suggestions ranging from a cloth merchant's wife to potentially being a disguised self-portrait of Da Vinci himself. However, these are just theories and the recognized self-portrait of Da Vinci is a separate piece.
Further confusion might arise from the Vitruvian Man, which although not a self-portrait, is a drawing by Da Vinci meant to depict ideal human body proportions and is still used in reference to the study of human anatomy and the Human Genome Project. The correct answer to the student's question about what Da Vinci's self-portrait is called is that it does not share a title with these other notable works and should simply be referred to as Leonardo da Vinci's Self-Portrait.