10 points!
which describes the process of fermentation?

a. aerobic process that manufactures pyruvate
b. aerobic process that restores nad+ supply
c. anaerobic process that manufactures pyruvate
d. anaerobic process that restores nad+ supply

d

Explanation:

The process of fermentation occurs when oxygen is not in sufficient supply in order to carry out aerobic respiration; it is an anaerobic process (which means a and b are wrong).

Glycolysis occurs as normal, with the production of two molecules of pyruvate (therefore, c  is wrong, as glycolysis is the process that manufactures pyrvuate). However, the cell will not proceed to the electron transport chain, where oxygen is required as the final acceptor.

Because of this, the electron transport chain won't proceed, and the NADH produced during glycolysis cannot drop off its electrons to form NAD+ - which is required in steady supply

Instead, the NADH donates its electrons to a derivative of pyruvate after glycolysis.  First,  pyruvate is converted into acetaldehyde, with the release of carbon dioxide. Then, NADH donates its electrons to acetaldehyde, turning it in to NAD+ and producing ethanol.

Therefore, fermentation is an  anaerobic process that restores NAD+ supply.