Answer:
Mitosis -
" The process of cell duplication, reproduction of the cell is said to be mitosis, in which from each cell having a set of genetic material is dividing into two identical daughter cells having the same number of chromosomes in it."
Step-by-step explanation:
So, option (A) is the best to chose from as, mitosis is the way through which multi-cellular organisms increase their number of cells.
As, the daughter cells created from the division of a single cell has the same number of chromosomes in it. But, the cell divides and through mitosis the cell generates more identical cells like itself.