Who was the first discoverer of an antibiotic?

The correct sequence of stages of the growth curve for bacteria is:

$A$ genetically engineered microorganism used successfully in bioremediation of oil spills is a species of

Alexander Fleming worked on which of the following bacteria?

Consider the following statements:
$I.$ Antibiotics are chemical substances produced by some microorganisms which can kill or retard the growth of other disease-causing microorganisms.
$II.$ Penicillin is the first antibiotic discovered by Alexander Fleming $(1928)$,while working on the bacterium $Staphylococcus$ $aureus$.
$III.$ The function of penicillin as an antibiotic was established by Ernst Chain and Howard Florey.
Which of the statements given above are correct?

Which of the following statements is $NOT$ true regarding antibiotics?