Final answer:
The most common location for a pericardial cyst is the right costophrenic angle. These fluid-filled sacs are mostly found on the right side and can be identified incidentally on chest imaging.
Step-by-step explanation:
The student has asked about the most common location for a pericardial cyst. The correct answer to this question is C. Right costophrenic angle. Pericardial cysts are uncommon benign congenital anomalies often located at the cardio-phrenic angles, particularly the right side. These are fluid-filled sacs that can be detected incidentally on chest imaging. While a pericardial cyst can be found in other areas like the hilum (option A), left costophrenic angle (option B), or superior mediastinum (option D), the right costophrenic angle is the most frequent location.