Updated: 4:38 PM EST Dec 21, 2020 President-elect Joe Biden promised to nominate a teacher for education secretary and could quickly put his choice into a political pressure cooker, as teachers unions balk at school reopening plans and Biden seeks to reopen most schools within 100 days of taking office.Biden s goal is to have his remaining Cabinet selections announced by Christmas, a transition official told CNN a timeline that means he would need to choose a nominee for education secretary within days.Click the video player above for more information on Sharon Contreras from WXII.The handful of candidates sources said were under serious consideration demonstrates the political pressures Biden is facing. Some would give his Cabinet more diversity, advancing an often-stated aim. Some would be welcomed by teachers unions, but could face fiercer Republican opposition in the confirmation process.Two of the contenders, according to a source familiar with the matter, are u