Right choice is (d) Phenyl acetic acid
To explain: Defined media contain specific amounts of pure chemical compounds with known chemical compositions. A medium containing glucose, (NH4)2SO4, KH2PO4, and MgCl2 is a defined medium. Complex media contain natural compounds whose chemical composition is not exactly known. Complex medium used in penicillin fermentation includes Phenyl acetic acid by continuous feed in a concentration of about 0.5-0.8% of total (g/liter).