The correct answer is option - cells begin to specialize.
Explanation:
Embryonic differentiation is a process in which the cell begins to divide and to be destined to make a specific cell line different from another cell. Each differentiated cell has fate to perform a specific function in later development in the body.
The embryonic cell differentiation takes place when the cell begins to specialize which is occurs after the cleavage of a zygote which triggers the differentiation process.
Thus, the correct answer is option - cells begin to specialize.
