The correct answer is option 3, fungus. Penicillin is extracted from a group of fungi known as Penicillium. This type of fungus produces a compound called penicillin, which is a powerful antibiotic. It was discovered by Sir Alexander Fleming in 1928 when he noticed that a mold had contaminated one of his bacterial cultures, killing off the bacteria. Since then, fungi from the Penicillium genus have been cultivated and used to produce penicillin through a process of fermentation.

Yeast, option 1, is a type of fungus, but it does not produce penicillin. Option 2, algae, is not related to the production of penicillin. Option 4, lichen, is a symbiotic association between a fungus and an alga, and it also does not produce penicillin.

Overall, penicillin is derived from specific species of fungi, particularly those belonging to the Penicillium genus.