Topic: Pair of Word,

Best Answer Explained in Below-:

The correct answer to the statement "Alexandar Fleming __ penicillin." is B) discovered. This choice is appropriate because it accurately reflects the historical context and the nature of Fleming's contribution to medical science.

In 1928, Alexander Fleming, a Scottish bacteriologist, made a groundbreaking observation when he noticed that a mold called Penicillium notatum had contaminated one of his petri dishes and was inhibiting the growth of bacteria. This serendipitous discovery led to the identification of penicillin as the first true antibiotic, which revolutionized medicine and has saved countless lives since its introduction.

The terms "invention" and "invented" imply the creation of something entirely new by human intervention, which does not apply here because penicillin already existed in nature. Similarly, "made" suggests a more active role in the fabrication of a substance, rather than the discovery of a naturally occurring biological phenomenon. Therefore, "discovered" is the most fitting term, as it acknowledges Fleming's role in recognizing and understanding the significance of penicillin, rather than suggesting that he manufactured or invented it.