It should be C! (: Fate mapping because it is used do dermine tissue linage!
While Differentiation is used when one cell type changes from one cell to another.
When it comes to the process an undifferentiated cell is already programmed to become a specific cell type by following a specified path towards cell differentiation.
I hope all is well, and you pass! (: Good luck, rockstar! If you need any further information, let me know. (:
