Final answer:
All the mentioned microorganisms, Penicillium, Streptomyces, and Bacillus, produce antibiotics including penicillin, streptomycin, and other antimicrobial agents.
Step-by-step explanation:
The group of microorganisms that produces antibiotics are fungi and bacteria such as Penicillium, Streptomyces, and Bacillus species. The first antibiotic discovered was penicillin, derived from Penicillium. Soil bacteria in the genus Streptomyces are known for their ability to produce a wide range of antimicrobials, and they have been a rich source of antibiotics since their discovery. In addition to these, Bacillus species, which are bacillus in shape, can produce endospores and are also used in the production of antibiotics. Therefore, the correct answer to the question 'Which of the following groups of microorganisms produces antibiotics?' is 4) All of the choices are correct.