Explanation:
Vaccination is a method of providing immunity against specific diseases. It involves the introduction of a pathogen or its components into the body to stimulate an immune response. The immune response leads to the production of antibodies and memory cells, which provide protection against future infections by the same pathogen.

The form of pathogen used in vaccination is typically inactivated and weakened (option B). Let's understand why this is the case:

Activated and strong pathogenic antigens:
- Using activated and strong pathogenic antigens in vaccines can be risky as they can cause severe illness or even death in individuals with compromised immune systems.
- This approach is more suitable for therapeutic purposes, such as cancer treatment, where a highly active immune response is needed to target specific cells.

Inactivated and weakened pathogenic antigens:
- Inactivated and weakened pathogenic antigens are safer to use in vaccines as they cannot cause the disease they are derived from.
- These antigens are obtained from the pathogen and treated in a way that reduces their virulence (ability to cause disease) while preserving their ability to induce an immune response.
- The treatment may involve heat, chemicals, or genetic modifications.
- The weakened pathogenic antigens are then introduced into the body through injection or oral administration.
- The immune system recognizes these antigens as foreign and mounts a response by producing antibodies and memory cells.
- The antibodies and memory cells provide protection against future infections by the same pathogen.
- Since the pathogen is weakened or inactivated, it does not cause the disease in vaccinated individuals.

Hyperactive and strong pathogen:
- The use of hyperactive and strong pathogens in vaccination is not recommended because it can overwhelm the immune system and lead to adverse reactions or complications.
- The goal of vaccination is to stimulate a controlled immune response, not to induce severe illness or harm.

Preformed antibodies:
- Preformed antibodies are not used as the form of pathogen in vaccination.
- Preformed antibodies are antibodies that have already been produced by another individual or animal.
- They can be administered in specific cases, such as passive immunization for immediate protection against certain diseases, but they do not provide long-term immunity like vaccines.

In conclusion, the most common form of pathogen used in vaccination is inactivated and weakened pathogenic antigens. This approach ensures safety while still eliciting a protective immune response against the targeted pathogen.