Explanation:

- The initial salary ratio of Abbi and Monu is 6:11.

- This can be taken as 6x for Abbi and 11x for Monu.

- Abbi's salary increase: 10% of 6x $$=>$$ $0.1\times 6x=0.6x$, making it $6x+0.6x=6.6x$.

- Monu's salary increase: 12% of 11x $$=>$$ $0.12\times 11x=1.32x$, making it $11x+1.32x=12.32x$.

- New salary ratio is $6.6x:12.32x$, simplifying to $66:123.2$.

- Simplify the ratio to approximately 3.3:6.16 or more accurately 33:61.6.

- Now, checking options:

- Option 1: 5:3 is far from the simplified ratio.

- Option 2: 15:28 roughly estimates to the required ratio.

- Option 3: 12:13 does not fit.

- Option 4: 17:23 also matches roughly close.

Thus, the right choice seems to be Option 2: 15:28