WASHINGTON — U.S. President-elect Donald Trump said Thursday he is choosing former Sen. David Perdue of Georgia to be ambassador to China. Trump said in a social media post that Perdue, a former CEO, “brings valuable expertise to help build our relationship with China.” Perdue pushed Trump’s debunked lies about electoral fraud during his failed bid for Georgia governor. Perdue lost his Senate seat to Democrat Jon Ossoff four years ago and ran unsuccessfully in a primary against Georgia Gov. Brian Kemp. Economic tensions will be a big part of the U.S.-China picture for the new administration. Trump has threatened