You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Alexander_Graham_Bell

Context:
Bell's coffin was constructed of Beinn Bhreagh pine by his laboratory staff, lined with the same red silk fabric used in his tetrahedral kite experiments. To help celebrate his life, his wife asked guests not to wear black (the traditional funeral color) while attending his service, during which soloist Jean MacDonald sang a verse of Robert Louis Stevenson's "Requiem":

Question:
What color silk was used in Bell's coffin?

red