Given the task definition and input, reply with output. Generate a correct and concise answer for the question based on the words in the context.

Context : The LD&ECR Class D was a class of nine 0-6-4T steam locomotives supplied to the Lancashire, Derbyshire and East Coast Railway in 1904 and 1906 by Kitson & Co. of Leeds.
Question : What was the year LD&ECR Class D entered service?
1904