Answer:
Option D, Condensation of ribulose 1,5 bisphosphate with carbon dioxide and splitting of a six-carbon product during the Calvin cycle.
Step-by-step explanation:
The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase commonly known as RuBisCO is utilized in the first step of calvin cycle in order to fix free carbon dioxide from atmosphere. It catalyzes the process that involves carboxylation or oxygenation of ribulose-1,5-bisphosphate commonly known as RuBP in the presence of carbon dioxide or oxygen . It can survive on its own and even after dying it helps in decomposition
Hence, option D is correct