China is prepared to step up its scrutiny of U.S. companies in the event President-elect Donald Trump takes punitive measures against Chinese goods and triggers a trade war between the world’s two biggest economies after he takes office, according to people familiar with the matter. The options include subjecting well-known U.S. companies or ones that have large Chinese operations to tax or antitrust probes, the people said, asking not to be identified because the matter isn’t public.