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During late-2013 through early-2014 NIST coordinated a special i-vector challenge based on data used in previous NIST Speaker Recognition Evaluations -LRB- SREs -RRB- .
 used for: NIST Speaker Recognition Evaluations -LRB- SREs -RRB-, i-vector challenge
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: conjunction, feature of, hyponym of, used for, part of, compare, evaluate for 
Text: {0} 
 Entity Pairs:  NIST Speaker Recognition Evaluations -LRB- SREs -RRB-, i-vector challenge 
Answer:
 used for: NIST Speaker Recognition Evaluations -LRB- SREs -RRB-, i-vector challenge