Try each option as Ishita's final salary and check whether removing the raise gives back a clean $2:3$ ratio.
If Ishita's final salary is $38000$, her original salary was $38000 - 4000 = 34000$.
Using the final ratio $40:57$, Ankita's final salary is $38000 \times \dfrac{40}{57} \approx 26667$, so her original salary was about $22667$.
Checking $22667 : 34000$, this reduces to almost exactly $2:3$, confirming the given original ratio.
None of the other options reduce back to a clean $2:3$ ratio after removing the Rs $4000$ raise.
\[\boxed{Rs. 38000}\]