Which of the following can the reader infer from this article?
A.
Research takes time and much effort from many people.
B.
There can be only one way to treat a bacterial infection.
C.
Millions of people every year come down with infection.
D.
After World War II, research on penicillin came to an end.

Heres the text
For the longest time, people have been afraid of infection. People tried to use herbal treatments to cure infection, but this was ineffective. Then, Louis Pasteur discovered that germs would not grow on a certain bread mold. Pasteur's discovery led to the study of antibiotics.
For many years, scientists tried to find out why germs would not grow on molds. This process was perfected when Sir Alexander Fleming made a breakthrough in 1928. His discovery was completely by accident. Fleming was known for being untidy. He had left a dish of bacteria out on a table overnight, and it became contaminated with a fungus. Fleming found that this fungus produced a substance he called penicillin. He then just needed to find a way to get the drug to the public.
Fleming worked hard for years to make his drug available to large numbers of people. The earliest form of the drug was a powder. The idea was to sprinkle the powder on the wound to treat infection. This did not work often because the drug did not get deep enough into a wound, and the patient would become infected.
About fifteen years later, two American companies discovered methods to make the drug on a large scale. They began selling penicillin to the public. Soon, everyone was recovering from bacterial infections, especially the type in wounds. This was good news, too. Nations around the globe had just become involved in World War II.