Classify the relation of question with context to one of these categories: 1) award received, 2) based on, collection, 3) conflict, 4) constellation, 5) convicted of, 6) date of death, 7) director, 8) drafted by, 9) educated at, 10) medical condition, 11) military branch, 12) narrative location, 13) occupation, 14) original network, 15) parent company, 16) point in time, 17) production company, 18) residence, 19) series, 20) service entry, 21) sex or gender, 22) spouse, 23) standards body question.
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Question: Context : The BMP-3 is designed and produced by the Kurganmashzavod (``Kurgan Machine Building Plant'') some variants however are built by the Rubtsovsk Machine Building Plant (RMZ), for example the BRM-3K. 
Question : What year was BMP-3 introduced?

Answer: service entry


Question: Context : Kristina Wayborn as Magda: trusted subordinate and henchman to Octopussy and Khan Kabir Bedi as Gobinda: 
Question : What is the series called that Octopussy belongs to?

Answer: series


Question: Context : Three Doors to Death is a collection of Nero Wolfe mystery novellas by Rex Stout, published by the Viking Press in 1950 -- itself collected in the omnibus volume Five of a Kind (Viking 1961). 
Question : The Three Doors to Death is part of a what series?

Answer:
series