TOKYO—Oil prices rose for a fifth straight day on Monday with Brent heading for $80 amid supply concerns as parts of the world sees demand pick up with the easing of pandemic conditions. Brent crude was up 92 cents or 1.2 percent at $79.01 a barrel by 0208 GMT, having risen a third consecutive week through Friday. U.S. Oil added 83 cents, or 1.1 percent to $74.81, near its highest since July, after rising for a fifth straight week last week. “Supply tightness continues to draw on inventories across all regions,” ANZ Research said in a note. Rising gas prices as also helping drive oil higher as the liquid becomes relatively cheaper for power generation, ANZ analysts said in the note. Caught short by the demand rebound, members of the Organization of the Petroleum Exporting Countries and their allies, known as OPEC+, have had difficulty raising output as under-investment or …