The best description of the inputs and outputs of mitosis in a multicellular organism is:
Input: A single cell ready to divide
Output: Two daughter cells that are genetically identical to the parent cell and each other.
This accurately reflects the process of mitosis, where one cell divides to form two identical daughter cells, maintaining the same genetic information. The other options mentioned involve differentiation and specialized cells, which are not the primary outcome of mitosis itself but rather the result of subsequent developmental processes.