Dark reaction gets completed by the regeneration of:

Explanation

In the third and final stage of the Calvin cycle i.e. regeneration of RuBP, 1 glyceraldehyde 3-phosphate molecule is used to create glucose or other organic compounds as it exits the cycle. The rest of the 5 glyceraldehyde 3-phosphate molecules are recycled to regenerate 3 molecules of RuBP to enable the Calvin cycle to continue.