**Core Concept:** Full mouth survey (FMS) is a comprehensive examination of all the teeth in the oral cavity. It is performed to assess the dental health status, detect dental caries, periodontal diseases, and other oral pathologies. In this case, the patient has multiple carious teeth and frequent snacking on sugary foods, leading to dental caries.

**Why the Correct Answer is Right:** For a full mouth survey of this patient, we would require at least two radiographs to cover all the teeth adequately. The rationale behind this is that a dental x-ray machine typically rotates around the patient's head, producing two images: a mesial view and a distal view for each tooth. Therefore, if we consider one quadrant at a time, we would need two radiographs to cover the entire mouth.

**Why Each Wrong Option is Incorrect:**

A. This option suggests that only one radiograph is required, which is incorrect as it does not cover all the teeth adequately.
B. This option suggests that three radiographs are needed, which is more than the correct number and would result in unnecessary radiation exposure.
C. This option suggests that four radiographs are needed, which is more than the correct number and would also result in unnecessary radiation exposure.
D. This option suggests that five radiographs are needed, which is more than the correct number and would result in excessive radiation exposure.

**Clinical Pearl:** When performing a full mouth survey, it is crucial to consider both mesial and distal views of each tooth to ensure complete evaluation of the dental condition. Over-exposure to radiation should be avoided to minimize potential harm to the patient. Thus, the correct answer is two radiographs per quadrant, for a total of four radiographs for a full mouth survey.