C is the correct choice. Reason why B is not correct because the time line of events is clearly stated in the sentence and we need not use past perfect tense 'HAD', in fact using simple past will be more precise.
Hope it helps. If it does, please give kudos

Production of the Ford Model T, which was colloquially known as the Tin Lizzie, commenced in 1908, during the presidency of Theodore Roosevelt, was not discontinued until nearly two decades later, during the presidency of Calvin Coolidge, who stimulated competition in the automobile industry by lowering corporate taxes and encouraging consumer spending.
A) which was colloquially known as the Tin Lizzie, commenced in 1908, during the presidency of Theodore Roosevelt,
B) colloquially known as the Tin Lizzie, had commenced in 1908, during the presidency of Theodore Roosevelt, and
C) which was colloquially known as the Tin Lizzie, commenced in 1908, during the presidency of Theodore Roosevelt, and
D) colloquially known as the Tin Lizzie and commenced in 1908, during the presidency of Theodore Roosevelt it
E) colloquially known as the Tin Lizzie, which had commenced in 1908, during the presidency of Theodore Roosevelt, and