If the Doctor stays in Kolkata, how many children does the teacher have?
2
CASE 1
No of childrenOfficeProfessionLocation0AlphaPilotChennai1GammaTeacher/Doctor/EngineerKolkata1BetaDoctor/EngineerDelhi2DeltaTeacher/EngineerMumbai
CASE 2
No of childrenOfficeProfessionLocation0AlphaPilotChennai1GammaDoctorKolkata1DeltaEngineerDelhi2BetaTeacherMumbai
this is case (2) as shown above