The price for oil produced by the Organization of the Petroleum Exporting Countries (OPEC) inched below the 40-dollar mark Tuesday, the Vienna-based cartel said Wednesday, according to DPA. One barrel (159 litres) of OPEC-produced crude stood at 39.34 dollars Tuesday, 0.96 dollars lower than on the previous day. It was the third time since early December that OPEC's basket price of 12 crude brands slid below 40 dollars.