When recruiting employees at Microsoft China, this question was asked: There are 12 small balls, of which only one is different in quality from the other 11. If you are only given three opportunities to test, in 30 minutes, how can you pick out This ball? The vast majority of candidates have gone through all their troubles and did not figure out the results within 30 minutes, and left only with regret. After 30 minutes, a young man was still thinking hard in the exam room and refused to leave. After a few hours, The youth is still sitting there doing experiments. The examiner asks after finding out, is there any result? The young man shook his head. In the end, this young man was hired by the company. The reason is: his intelligence and ability are certainly not good enough, but he has perseverance; a successful business wants sustainable development. In addition to innovative consciousness and ingenuity, it needs to be persistent. And this young man embodies this spirit. What's best for the text title of this paragraph? ['Recruitment challenges.', 'IQ test.', 'Microsoft recruits "stupid people".', 'Businesses need persistent youth.']