Consider the following statements regarding microtubules and choose the correct answer:
1. The wall of a microtubule is made of 13 longitudinal filaments, each a polymer chain of tubulin
2. Microtubules help in the maintenance of cell form, cell mobility and movement of chromosomes
3. Microtubules occur only in bundles in the cytoplasm

A. 1 and 2 are correct

B. 1 and 3 are correct

C. 2 and 3 are correct

D. 1, 2 and 3 are correct

Answer: Option A