For a periapical image, which criteria must be fulfilled?

For a periapical image to be considered diagnostic and meet the required criteria, it is essential for the entire tooth to be visible along with an adequate view of the surrounding structures. Specifically, this includes capturing the entire length of the tooth, extending at least 2 mm beyond the apex of the root. This criterion ensures that any potential pathological conditions that could affect the root or surrounding periapical area are adequately visualized.

Having the full tooth visible is crucial for a thorough evaluation, as it allows dental professionals to assess factors like root length, canal anatomy, and periapical lesions, which are vital for diagnosis and treatment planning. The other options focus on limiting the view to certain parts of the tooth, which would not provide a complete picture necessary for proper assessment. This makes option A the correct choice, as it emphasizes comprehensive visualization, which is essential for effective dental radiography practice.