45. In the global carbon cycle, plant photosynthesis plays a key role in fixing inorganic carbon. What is the enzyme in the chloroplast responsible for catalyzing the binding of carbon dioxide to RuBP? (A) PEP carboxylase (B) Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) (C) ATP synthase (D) NADP⁺ reductase