The right answer is 4).
The cytoskeleton is made up of biological polymers of proteins, sometimes called fibers because of their large size at the cellular level. They are classified into three categories:
Microfilaments: involves in cytoplasmic phenomena (division, endocytosis, migration).
Intermediate filaments: Maintenance of the nucleus structure.
Microtubules: Involved in the separation of chromosomes during mitosis.
