Given the task definition and input, reply with output. In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: He was then assigned to the Nautical Almanac Office of the US Naval Observatory Link Information: after which he was assigned for two years at the Bureau of Navigation. Question: Which of the offices that Charles E. Vreeland worked at is the oldest?
Answer: the Nautical Almanac Office