What was Gajanan Maharaj's response when Ratanji offered him a flower garland and fruits in the Masjid?

The provided text does not describe an encounter between Ratanji and Gajanan Maharaj. The events you are asking about actually concern Sai Baba. As detailed in Chapter 14, Ratanji traveled to Shirdi and went to the Masjid for darshan. It was there that he met Sai Baba, whom the text refers to as "Maharaj, the heap of merit." Ratanji placed a flower garland around Sai Baba's neck and offered fruits at His feet. In response, Baba asked Ratanji what Dakshina (offering) he would give, a practice He commonly employed with visitors of any faith.