I need help on my finales !! Read this paragraph.

Before the Rosetta Stone was discovered in 1799, no one knew how to read Egyptian hieroglyphic writing. Its meaning had been lost for almost 1400 years. But countless visitors to Egypt over the centuries had tried to decipher the mysterious symbols. This is the story of their attempts, and of how the Rosetta Stone finally enabled scholars to unlock the Egyptian past.

Which sentence states a position that the author plans to prove in The Riddle of the Rosetta Stone?

A.) Before the Rosetta Stone was discovered in 1799, no one knew how to read Egyptian hieroglyphic writing.
B.) Its meaning had been lost for almost 1400 years.
C.) But countless visitors to Egypt over the centuries had tried to decipher the mysterious symbols.
D.) This is the story of their attempts, and of how the Rosetta Stone finally enabled scholars to unlock the Egyptian past.