Answer: a. large, fairly rigid block.
Step-by-step explanation:
A tectonic plate is part of the Earth’s lithosphere and can be best described as:
a large, fairly rigid block.
Tectonic plates are the large, rigid pieces of the Earth's lithosphere that fit together in a way similar to a jigsaw puzzle to form the Earth's crust. These plates move and interact at their boundaries, leading to various geological phenomena such as earthquakes, volcanic activity, and the creation of mountain ranges.