Dec 12 (Reuters) - Futures tied to Canada's resources-heavy main stock index were marginally higher on Tuesday, tracking a rise in metal prices, while investors awaited the latest U.S. inflation data to gauge the Federal Reserve's interest rate trajectory. ET, which comes a day before the U.S. central bank is set to announce its decision on monetary policy, with consensus tiled towards the Fed keeps its rate steady. Among individual stocks to look out for, brokerage RBC upgraded Canada's largest insurer Manulife Financial MFC.TO to "outperform" from "sector perform".