The correct option is C Cell wall
Cell wall was discovered by Robert Hooke, in 1665, when he saw an empty box like compartments in a very thin slice of cork under his microscope. He wrote a book Micrographia and coined the term Cellula which was later on changed into cells. Robert Hooke thought cells to be passages for conducting fluids. Actually, he had observed compartments made up of the cell wall and not true living cells.