The correct option is C Small pox - Variola, Chickenpox - Vericella, German measles - Rubella, Athlete's foot - Trichophyton, Filariasis - Wuchereria.
Athlete's foot is a fungal infection, caused by Trichophyton. German measles is also called as Rubella, which is a highly contagious disease caused by Rubella virus.
Filariasis is a parasitic disease caused by infection with roundworms, Wuchereria bancrofti.
Smallpox is a contagious, disfiguring and often deadly disease that has affected humans for years and is caused by Variola major virus.
Chicken pox is a contagious illness that causes the itchy rash and red spots and is caused by varicella-zoster virus.
Thus, the correct answer is option (C).