Question

Fungi produce many compounds that humans are able to use medically. how can you account for these compounds?

Answer 1

None of those options are correct. 

Fungi produce,naturally, antibiotics that will kill or inhibit the growth of bacteria.
This is useful for them to limit competition in their natural environment but it's also useful for us because it will kill bacteria that cause us infections.

The only thing scientists had to do is isolate that antibiotic.

Some antibiotics that were developed from fungi: penicillin and cephalosporins.