Where does fertilisation take place in humans?

The correct answer is Option (3) → In the fallopian tube.

Fertilisation is the fusion of a sperm with an ovum. It can take place only where the two meet. The fallopian tube (oviduct) carries the ovum from the ovary towards the uterus, and its widest part is the ampullary region. The sperms swim up through the cervix and the uterus into this tube, and the ovum is brought to the same spot, so fertilisation takes place in the fallopian tube.

The ovary only releases the ovum, and the cervix and the uterus are only passages for the sperms. The uterus becomes important later, when the embryo reaches it and gets implanted in its wall.

NCERT Extract:
Fertilisation and Implantation – “During copulation (coitus) semen is released by the penis into the vagina (insemination). The motile sperms swim rapidly, pass through the cervix, enter into the uterus and finally reach the ampullary region of the fallopian tube (Figure 2.11b). The ovum released by the ovary is also transported to the ampullary region where fertilisation takes place.”