Which of the following pairs is correct?

Observe the given figure carefully and identify the site of fertilization by considering the parts labeled as $a, b, c,$ and $d$.

Which of the following statements are true about the female reproductive system?
$(A)$ Both estrogen and progesterone are necessary for development of follicle
$(B)$ Progesterone production is under the control of $LH$
$(C)$ The part of the oviduct is isthmus; has a narrow lumen and it joins the uterus
$(D)$ During pregnancy all events of the menstrual cycle stop and there is no menstruation
$(E)$ The graafian follicle ruptures to release the primary oocyte from the ovary by the process called ovulation

Genetic recombination is due to .....

Fraternal twins are produced when

If the number of chromosomes in most body cells of a mammal is $40$,the cells in the seminiferous tubule will have