Final answer:
The correct completion of the imagined line of the dog saying “for god's sake” from 'The Dean's December' referenced by Rushdie is not determinable from the provided text extracts.
Step-by-step explanation:
The student is asking about a specific line from Salman Rushdie's reference to a scene in Saul Bellow's novel 'The Dean's December'. The correct completion of the dog's imagined line “for god's sake” is not found in the provided extract of texts. These extracts do not include the scene from 'The Dean's December' described by the student; hence, the correct answer to the student's question is not determinable based on the given references.