The correct option is B Artificially acquired active immunity
Vaccination is an example of artificially acquired active immunity where dead or attenuated pathogen is introduced into the individual and the body produces antibodies against it and hence acquiring immunity.
Antivenom and antitoxins are examples of artificially acquired passive immunity. In this case, readymade antibodies that are produced in vitro are introduced in patients to immediately fight against the venom or toxins.
IgG obtained by the foetus from the mother through placenta is an example of naturally acquired passive immunity. In this case the antibodies produced by the mother's body is transmitted to the foetus.
The direct exposure to the antigen, results in naturally acquired active immunity. The pathogen enters the body and in response to this the individual produces B and T lymphocytes and thereby produces antibodies to fight against the pathogen.