In a lead-acid cell, if the specific gravity of sulphuric acid is 1.8, it will require following ratio of acid to water to get mixture of specific gravity of 1.3
A. 6 parts of acid to 4 parts of water
B. 4 parts of acid to 4 parts of water
C. 4 parts of acid to 6 parts of water
D. 4 parts of acid to 8 parts of water