Please answer the following question: Here's a logic test: A student slides an eraser over the chalkboard to clean it, then slides the eraser across the brick wall next to the chalkboard. The eraser moves slides faster across the chalkboard than it does the brick wall because the smoother surface is (A) the chalkboard (B) the brick wall. Choose the answer between "chalkboard" and "brick wall".
A:
chalkboard