Which bacterial strain, developed from natural isolates by genetic manipula- tions, can be used for treating oil spills?

1. The question asks about a bacterial strain used for treating oil spills, which was developed from natural isolates by genetic manipulations. 2. This specifically refers to the pioneering work done by Dr. Ananda Chakrabarty in the 1970s. 3. He used genetic manipulations (combining plasmids) to create a novel strain of bacterium capable of degrading multiple components of crude oil more effectively than natural isolates alone. 4. The bacterial genus he worked with and modified was Pseudomonas. 5. Therefore, Pseudomonas (D) is the correct answer, referencing this specific development in bioremediation technology using genetically engineered microorganisms. 6. Agrobacterium (A) is used in plant genetics, Clostridium (B) has various roles but not primarily oil degradation, and Nitrosomonas (C) is involved in the nitrogen cycle.