Final answer:
The origin point of an earthquake on a fault is known as the focus, which is not to be confused with the epicenter or other related geological features such as a fault scarp. Hence, the correct answer is option A.
Step-by-step explanation:
The point on a fault where an earthquake occurs is called the focus of the earthquake. This point is located beneath the Earth's surface where the rupture along the fault begins. The epicenter, on the other hand, refers to the point on the Earth's surface directly above the focus.
The surface rupture, seismic point, and scarp are related terms, but they do not define the origin of an earthquake. Describing faults and earthquakes is integral to the study of plate tectonics, implying how tectonic plate movements can generate earthquakes through the built-up stresses causing sudden slippages along faults like the San Andreas Fault.