Final answer:
Loeffler medium promotes the production of brown metachromatic granules in Corynebacterium diphtheriae through a specific staining process using methylene blue.
Step-by-step explanation:
Loeffler medium stimulates growth and production of metachromatic granules in Corynebacterium diphtheriae. These granules contain polyphosphate and are thought to serve as phosphate reserves.
Loeffler medium is enriched with serum, which supports the growth of C. diphtheriae and promotes the formation of the characteristic blue-black or brownish-black granules when stained with methylene blue. The correct answer to the question is b) Brown granules. This specific growth media is often used in clinical microbiology to identify C. diphtheriae, the bacterium responsible for causing diphtheria.