What Evidence in the Ocean Floor Is Indicative of Past

Multiple Choice

What evidence in the ocean floor is indicative of past magnetic reversals?

A) Magnetic particles in basalt orient with the magnetic field in force at the time the oceanic lava cooled and hardened.
B) Isotopic analysis of ocean core sediments help determine sea floor age and this can be used to infer past magnetism.
C) The ocean floor is uniformly old,preserving Earth's 4.6 billion history.
D) Mantle hot spots are always oriented to the magnetic field.