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.

Context : Virtually all battles that are considered part of the 'Battle of the Border' (with the exception of the Battle of Hel, which lasted for more than a month and the Battle of Mokra, a Polish defensive victory) resulted in rapid defeat of Polish forces, which were forced to abandon the regions of Pomerania, Greater Poland and Silesia. 
Question : When did Battle of the Border occur?
point in time

Context : Warren McGlone (born September 17, 1969, in Philadelphia, Pennsylvania), known by the stage name Steady B, is an American hip hop emcee who, along with Schoolly D, the Fresh Prince, and Three Times Dope, was one of the first wave of Philadelphia-area emcees to gain notoriety in the mid to late 1980s. 
Question : Which crime led to the conviction of Steady B?
convicted of

Context : Tupolev OKB was founded by Andrei Nikolayevich Tupolev in 1922. 
Question : What company is Tupolev part of?

parent company