英语翻译As the economic market environment becomes more and more

英语翻译
As the economic market environment becomes more and more competitive ,many companies come to realize the importance of keeping track of customer satisfaction,or how their customers services are responding to their products and services.They know that no matter the feedback is positive or negative (负面的),their willingness to recognize it and respond actively can help clients transform (转变) one-time buyers into lifelong 4)___________.
第4中应该填哪个单词?“clients,source,complaints,improving,position,conduct,cooperation”
只翻译这句：their willingness to recognize it and respond actively can help clients transform (转变) one-time buyers into lifelong 4)___________.