Answer:
a. Rifts
Explanation:
A fault (c) happens at all plate boundaries, so while this is true, it is not the most correct. A subudction zone (b) is where Earth's tectonic plates dive down into the mantle, so this does not answer our question. A rift, in general, is a crack, split, or break in something. A rift in plate tectonics is when plates are moving apart from each other, caused be tension, so a is our answer.
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- Heather
