hey
i think maybe bajaj's real kid either got kidnapped like tulsi' ansh by some1 else and prerna wid the help of this rana guy replaced it wid kasak....and kasak is probably this rana guy's daughter but not prerna's get it?
OR
that bajaj's real kid died...and the rest same as above ie prerna was given some1 else's child who she passed off as her own and bbajaj's