The correct answer is A. 9.
A centriole is a cylindrical organelle found in animal cells. It is made up of nine triplets of microtubules arranged in a ring. The microtubules are made up of the protein tubulin. The centrioles are involved in cell division, and they also help to organize the cell’s cytoskeleton.
Option B is incorrect because a centriole does not consist of 8 microtubules.
Option C is incorrect because a centriole does not consist of 7 microtubules.
Option D is incorrect because a centriole does not consist of 6 microtubules.