DOCTOR

$\backslash$table$[[$DoctorID$,$Name,DateOfMDGraduation,NumberOfPatients$],[$D$111,$John,$\frac{1}{1}\frac{?}{1999},100],[$D$222,$Tina,$\frac{1}{2}\frac{?}{2003},117],[$D$333,$Ellen,$\frac{1}{1}\frac{?}{2001},117],[$D$444,$Tina,$\frac{1}{1}\frac{?}{2003},144]]$

Which of the following functional dependencies does NOT exist in the table DOCTOR?