Match the antibiotics in column I with their microbial sources in column II:

Step 1: Antibiotics are matched with their microbial sources based on their discovery and production:
- (a) Chloromycetin (Chloramphenicol): Produced by Streptomyces venezuelae (3).
- (b) Erythromycin: Produced by Streptomyces erythreus (4).
- (c) Streptomycin: Produced by Streptomyces griseus (1).
- (d) Terramycin (Oxytetracycline): Produced by Streptomyces aurifaciens (2).
Step 2: Thus, the matches are: (a)-(3), (b)-(4), (c)-(1), (d)-(2).

