Which is a function of cyclins? A) Cyclins are carbohydrates that regulate DNA during the mitosis phase of the cell cycle. B) Cyclins are glycoproteins that repair DNA in the beginning of the cell ccle. C) Cyclins are proteins that regulate when and how often a cell divides

Cyclins are proteins, not carbohydrates: we can exclude option A because of this.

Cyclins have a regulatory function during the cell cycle, that is during the process in which the cell divides: so the best answer is C) Cyclins are proteins that regulate when and how often a cell divides