Around which river is Port wine traditionally produced?

Option A

Around which river is Port wine traditionally produced?

The Douro vinhateiro (winegrowing), an area of the Douro Valley in Portugal long devoted to vineyards, has been designated by UNESCO as a World Heritage Site. Traditionally, the wine was taken downriver in flat-bottom boats called rabelos, to be stored in barrels in cellars in Vila Nova de Gaia, just across the river from Porto. In the 1960s and 1970s, dams with locks were built along the river, allowing river traffic from the upper regions in Spain and along the border. Nowadays Port wine is transported to Vila Nova de Gaia in tanker trucks.