The correct option is A the ovum is fertilised externally and thereafter implanted in the uterus
The term ‘test tube baby’ refers to the product of IVF. IVF stands for in vitro fertilisation, which refers to the procedure where the sperm and oocyte collected from either the parents or donors are made to fertilise in vitro (in a petri culture dish, outside the body of the female). In other words, the ovum is fertilised in an external environment (simulated mostly according to the internal environment of a female) and then the resulting zygote is transferred into the female reproductive tract where it gets implanted.
The test tube baby is not fully developed in a test tube. Only the initial stages of development are carried out in a petri dish. The rest of the developmental stages are carried out in vivo.
Tissue culture refers to the process in which animal or plant tissues are cultured in an artificial culture media outside the body of the parent organism. Again, the full developmental process is not carried out using culture techniques in case of IVF.
If an individual develops from a non-fertilised oocyte, it would be considered a case of parthenogenesis. Parthenogenesis is not naturally seen in the case of humans.