32 years old patient came to your dental office, suffering from a bad odour and taste from His mouth.. separation between the abutment and the retainer

32 years old patient came to your dental office, suffering from a bad odour and taste from His mouth. By examination patient has an anterior mandibular 3 unit bridge that bubbles upon Applying water spray and slight pressure. Cause:
A) broken abutment.
B) Food impaction underneath the pontic.
C) separation between the abutment and the retainer.. *** (dissolving of cement / microleakage).