OPTION 3 i.e. C.'Better' is used which is the comparative degree of the adjective 'good'.The comparative degree is used while comparing two THINGS. In the GIVEN sentence, the climate of the two PLACES has been compared. When one thing is compared with another thing then we should always write 'that of' incase of singular comparison and 'those of' in case plural comparison after the comparative degree of the adjective in that sentence.Here, 'climate' is singular so we must use 'that of'.Correct sentence- The climate of Mumbai is better than that of Hyderabad.