Correct Answer: 96 : 80

Solution : Let's check the options —

First option: 104 : 78; The highest common factor is 26. Dividing both numbers by 26 gives the ratio 4 : 3

Second option: 96 : 80; The highest common factor is 16. Dividing both numbers by 16 gives the ratio 6 : 5. This option is different from the other options.

Third option: 64 : 48; The highest common factor is 16. Dividing both numbers by 16 gives the ratio 4 : 3

Fourth option: 80 : 60; The highest common factor is 20. Dividing both numbers by 20 gives the ratio 4 : 3

Hence, second option is correct.