It’s D, cognitive. Cognitive development has to do with the mind.
Cells are made of the same DNA but they can have different functions. It depends on where they are in your body; each of them have a separate job. There are different types of cells. Apparently, for a cell to work...1000 proteins must be made.
You should move this question to Mathematics instead. Or at least physics.
The answer would be a. hope that helped