The correct option is 12.5%.

Let us break down the solution step-by-step:

Step 1: Calculate the initial number of ITOs recruited by Bank A and Bank C
From Table-1, the total number of vacant posts in Bank A is 800, and in Bank C is 600.
From Table-2, the requirement of IT Officers (ITO) in any bank is 11% of its total vacant posts.

The number of ITOs initially recruited by Bank A is:
$$\text{Initial ITOs in Bank A}=800\times \frac{11}{100}=88$$
The number of ITOs initially recruited by Bank C is:
$$\text{Initial ITOs in Bank C}=600\times \frac{11}{100}=66$$

Step 2: Find the number of ITOs who transferred from Bank A to Bank C
Let $x$ be the number of ITOs who left Bank A and joined Bank C.
After this transfer, the number of ITOs in both banks became equal. Therefore, we can write the equation:
$$88-x=66+x$$
Solving for $x$:
$$88-66=2x$$
$$2x=22$$
$$x=11$$
Thus, 11 ITOs left Bank A to join Bank C.

Step 3: Calculate the percentage of new recruits who left Bank A
The percentage of ITO recruits who left Bank A is calculated as the ratio of those who left to the initial number of ITO recruits in Bank A, multiplied by 100:
$$\text{Percentage}=\left(\frac{11}{88}\right)\times 100\%$$
Simplifying the fraction:
$$\text{Percentage}=\frac{1}{8}\times 100\%=12.5\%$$