On fertilization of egg nucleus with sperm nucleus

The correct option is D Embryo is formed
When the egg nucleus and the sperm nucleus unites in the fallopian tube, it results in fertilization. And it results in the production of zygote or fertilized egg. Maturation is completed during the the gametogenesis (before the formation of egg / sperm) and the polar body is also formed during this process.
Thus, the correct answer is option C.