The correct order of the phases of a stem cell is:
Gene expression, mitosis, differentiation.
However, if this specific option isn't provided, the most logical choice from the given responses is:
Gene expression, differentiation, mitosis.
But strictly according to stem cell development, engaging in gene expression informs what kind of cells the stem cell will differentiate into after mitosis. The timeline and specific phrasing matter.
Given the provided options, I would suggest using:
Gene expression, differentiation, mitosis if it's present or relying on the standard progression if adjusted wording is accepted.