Answer
Three.
Work Step by Step
Three plane mirrors produce the multiple images of the person. This is a kaleidoscope, and the edges of the 3 mirrors are visible in the photo.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.