The correct option is B Schleiden and Schwann
Matthias Schleiden and Theodore Schwann together formulated the cell theory.
(i) All living organisms are composed of cells and products of cells
Rudolf Virchow was the third scientist who also contributed to the cell theory. He added the following tenet to the cell theory
(ii) All cells arise from pre-existing cells.
Anton von Leeuwenhoek - First to see and describe a live cell
Robert Brown - First to discover the nucleus