Professional negligence by a medical professional that results in the death of a patient is most commonly prosecuted under Section 304A of the IPC, which deals with "Causing death by negligence." This section applies to deaths caused by a rash or negligent act not amounting to culpable homicide. It's important to note that the Supreme Court, in cases like *Jacob Mathew v. State of Punjab*, has established a very high standard of 'gross negligence' for holding a doctor criminally liable, to protect them from frivolous litigation. The other sections are irrelevant: 302 is for murder, 305 is for abetment of suicide of a child, and 303A does not exist.