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