Final answer:
The secondary oocyte becomes an ovum during fertilization in the fallopian tube.
Step-by-step explanation:
The secondary oocyte becomes an ovum, the mature female reproductive cell, when the second meiotic division occurs. This second meiotic division, commonly known as meiosis II, only resumes and is completed if a sperm cell successfully fertilizes the secondary oocyte. This critical event takes place during fertilization in the fallopian tube, not in the uterus, cervical area, or vagina. Thus, the correct answer to when and where the secondary oocyte becomes an ovum is b) Fertilization; fallopian tube.
This occurs during ovulation in the fallopian tube. If the secondary oocyte is fertilized by a sperm, it continues through meiosis II, producing a second polar body and a fertilized egg containing all 46 chromosomes of a human being.