Area of irregular, seismically inactive topography marking the position of a once-active transform fault.

• A. Abyssal Plain
• B. Continental Margin
• C. Fracture Zone
• D. Epicenter

Answer: (C)

Fracture zones are long, irregular scars on the ocean floor that trace the outline of a transform fault but have become seismically inactive. They form as plates slide past each other at mid-ocean ridges and then continue beyond the active fault as a record of past motion. The description—irregular topography on the seafloor that marks where a transform fault lies, yet is not currently seismically active—fits fracture zones best. Other features don’t match: an abyssal plain is a broad, relatively flat area of the deep ocean; a continental margin lies where oceanic and continental crust meet; an epicenter is a point on the Earth's surface above an earthquake’s origin.