How Does One Account for the Bubbles in a Glass

How does one account for the bubbles in a glass of beer or champagne?

A) Bubbles of CO₂, produced by aerobic respiration in yeast cells, were trapped in the beverage at bottling.
B) Bubbles of CO₂ were formed by the yeast cells during glycolysis.
C) The bubbles are simply air bubbles resulting from the brewing process.
D) Bubbles of CO₂ were produced by yeast during anaerobic metabolism and were trapped in the bottle.
E) Lactate fermentation accounts for the bubbles.