Earlier in the body of text this question was provided for, you should be able to find the passages: "No matter where you walk, you are walking on the crust of the earth. You would be on the crust even if you were walking along the bottom of the ocean." and "The lithosphere is the crust and the uppermost, rigid portion of the mantle. The crust can vary in thickness, and is made of two different types: oceanic crust and continental crust."
Answer: Lithosphere