Which of the following is the abbreviation for an electrocardiogram?

The abbreviation for an electrocardiogram is commonly referred to as both EKG and ECG. This dual usage arises from the fact that "ECG" is derived from the English term "electrocardiogram," while "EKG" comes from the German "Elektrokardiogramm." Both abbreviations are widely accepted in the medical community and are used interchangeably to represent the same diagnostic test that records the electrical activity of the heart. Therefore, the correct answer effectively captures the accepted terminology for this important medical procedure.