Detailed Instructions: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Q: Passage: Russian border troops were stationed along the TajikAfghan border until summer 2005. Since the September 11, 2001 attacks, French troops have been stationed at the Dushanbe Airport in support of air operations of NATO's International Security Assistance Force in Afghanistan. United States Army and Marine Corps personnel periodically visit Tajikistan to conduct joint training missions of up to several weeks duration. The Government of India rebuilt the Ayni Air Base, a military airport located 15 km southwest of Dushanbe, at a cost of $70 million, completing the repairs in September 2010. It is now the main base of the Tajikistan air force. There have been talks with Russia concerning use of the Ayni facility, and Russia continues to maintain a large base on the outskirts of Dushanbe.
A:
What troops were stationed along the Tajik-African border?