Correct Answer - Option 3 : Rama
Logic: We have to find who is the eldest person as per the given conditions.
Geeta is older than Mohini but younger than Rama.
Rama > Geeta > Mohini.
Now, Mohini is older than Sonia but younger than Rama.
So, the Final arrangement should be:
"Rama > Geeta > Mohini > Sonia.
As it can be seen that Rama is the eldest among the four persons.
Hence, the correct should be "Rama".