The oxidative phase of the pentose phosphate pathway
a. reversible under physiological conditions.
b. has an enzyme requiring thiamine pyrophosphate as a coenzyme.
c. produces ribulose‑5‑phosphate and nadph for biosynthetic processes.
d. converts pentoses to hexoses.

C: Produces ribulose-5-phosphate and NADPH for biosynthetic processes.

Explanation:

There are two distinct phases in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of 5-carbon sugars. For most organisms, the pentose phosphate pathway takes place in the cytosol; in plants, most steps take place in plastids.