What does $Rauwolfia$ $vomitoria$ produce?

Which bacteria was being cultured by the discoverer of the first antibiotic at the time of its discovery?

Consider the following statements $(A-D)$ about organic farming.
$(A)$ Utilizes genetically modified crops like Bt cotton
$(B)$ Uses only naturally produced inputs like compost
$(C)$ Does not use pesticides and urea
$(D)$ Produces vegetables rich in vitamins and minerals
Which of the above statements are correct?

$A$ pure culture of bacteria was first obtained by..........

The term $LABS$ abbreviates as:

The first antibiotic was discovered accidentally by $A$ while working on $B$.