The correct choice to complete the text in a way that conforms to the conventions of Standard English is:
(Choice A) California
This is the most straightforward option and does not require additional punctuation that would disrupt the flow of the sentence. The correct sentence would read:
"In 2008, two years after the death of science fiction writer Octavia Butler, the Huntington Library in California received a collection of more than 8,000 items, including Butler’s private notes, research materials, manuscripts, photos, and drawings."