Match List-I (Operons) with List-II (Number of structural genes) and select the correct answer: List-I List-II a. Ara Operon of E. coli 1. 9 structural genes b. His Operon of Salmonella typhimurium 2. 4 structural genes c. Trp Operon of E. coli 3. 5 structural genes d. Leu Operon 4. 3 structural genes