Which is not a product of fermentation?

Which one of the following reactions represents anaerobic respiration?

When a molecule of pyruvic acid is subjected to anaerobic oxidation and forms lactic acid,there is

Given below are two statements.
$Statement-I$ - Skeletal muscles usually derive energy by anaerobic respiration.
$Statement-II$ - After vigorous exercise,lactic acid accumulates in muscle fibres,leading to muscle fatigue.
In the light of the above statements,choose the most appropriate answer from the options given below:

An energy-releasing metabolic process in which a substrate is oxidized without an external electron acceptor is called ........

Anaerobic respiration occurs in the ......