Generate a correct and concise answer for the question based on the words in the context.

Ex Input:
Context : The Mark 10 torpedo was a torpedo put into use by the United States in 1915. 
Question : In what year did Mark 10 torpedo enter service?

Ex Output:
1915


Ex Input:
Context : The Type 97 motorcycle, or Rikuo, was a copy of a Harley-Davidson motorcycle produced from 1935 in Japan under license from Harley-Davidson by the Sankyo Company (later Rikuo Nainen Company). 
Question : What was the year Type 97 motorcycle entered service?

Ex Output:
1935


Ex Input:
Context : The Bell P-63 Kingcobra is an American fighter aircraft developed by Bell Aircraft in World War II from the Bell P-39 Airacobra in an attempt to correct that aircraft's deficiencies. 
Question : Which is the basis of Bell P-63 Kingcobra?

Ex Output:

Bell P-39 Airacobra