The drawing shows three blocks, each with the same mass, sta…

The drawing shows three blocks, each with the same mass, stacked one upon the other. The bottom block rests on a frictionless horizontal surface and is being pulled by a force F→{“version”:”1.1″,”math”:”F→”} that is parallel to this surface.  The surfaces where the blocks touch each other have identical coefficients of static friction. Which one of the following correctly describes the net force of static friction fs{“version”:”1.1″,”math”:”fs”} that acts on each block? Record your answer with your reasoning to your scratch paper. Make sure to submit it to Gradescope at the end of the exam. (10 points)