Correct Answer :
Microtubules are the largest cytoskeletal filaments in cells and found throughout the cytoplasm. They are filamentous intracellular structures that are responsible for various kinds of movements in all eukaryotic cells. They are involved in nucleic and cell division, organization of intracellular structure, and intracellular transport, as well as ciliary and flagellar motility. They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin.