A nursing student develops a positive reaction to the tuberculin skin test. A history reveals possible exposure to patients with tuberculosis. A sputum sample is acid-fast negative. When asked for vaccination records, the student reports that childhood vaccination records were lost when the family emigrated from a Southeast Asian country. What is the best explanation for the test results?
A) The student has been infected with Mycobacterium tuberculosis. B) The student has been exposed to Mycobacterium tuberculosis. C) The student is not infected. D) The student has been exposed to Mycobacterium tuberculosis or was vaccinated with BCG vaccine. E) No conclusion is possible with the information provided.