In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.

Context: He attended the Higher Command and Staff Course, graduating in April 1991 Link Information: The Higher Command and Staff Course is a staff course for senior military officers of the United Kingdom armed forces and allies. Answer: United Kingdom 
In which country did Trousdell attend school as an officer?

Context: Collard made his debut for Cambridgeshire in the 1971 Minor Counties Championship against Bedfordshire Link Information: A county organisation has been traced back to May 1847 and a Bedfordshire team competed in the very first Minor Counties Championship in 1895 Answer: 1895
When did the team Collard made his debut against compete in its first Minor Counties Championship?

Context: though in the last decades, the Avar Khaganate had to deal with Bulgarian and Croat incursions Link Information: They are probably best known for their invasions and destruction in the Avar–Byzantine wars from 568 to 626. Answer: 568 to 626

How many years did the ruler who had to deal with Bulgarian and Croat incursions rule the area?