I answered 39 questions out of which 9 are zero score accepted answers.
Why did I am not awarded the Tenacious badge?
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When your zero-score accepted answers are all at least 10 days old and still at 0 votes, then the total count of accepted answers is taken into account.
Not all of those 0-score answers are old enough; I count 5 that are 10 days old or more, and with 39 accepted answers you need 8. In a few days time, if all those 0-score answers are still at 0, and you didn't add more accepted answers to your total, you'll be awarded the badge.