Magnetic readings taken accross mid-ocean ridges provide evidence that

a. the sea-floor is spreading
b. the ocean basins are older than the continents
c. the mid-ocean ridges are higher than the nearby plains
d. Earth's rate of rotation has changed

The magnetic readings taken across mid-ocean ridges provide evidence that "the sea-floor is spreading".

Option: A

Explanation:

As researchers analyzed trends in the ocean floor rocks, they noticed further encouragement for expanding the seafloor. Previously we read that Earth is behaving like a giant magnet, with a north pole and a south pole. Remarkably, throughout the Earth's past, Earth's magnetic poles flipped themselves several times.

The last turnaround occurred nearly 780,000 years ago. If the magnetic poles now unexpectedly flipped, one would find its compass needle pointing south. Researchers have found that the rock forming the ocean floor contain iron and thus resides in a form of magnetized stripes.

c. is the correct answer