Answer:
B) mutagens
Step-by-step explanation:
Mutagens are substances that causes mutation. Mutation involves alteration of the genetic materials of an organism.
Substances such as ultra-violet radiation, x-rays, nitrous acid, viruses, fungal-infections e.t.c leads to the physical, chemical and biological alteration of genetic sequences to produce a mutant. A mutant is an organism whose genetic sequence has been altered.
Note: Pathogens are disease causing organisms. Vectors are carriers of pathogens.