The change in quantity supplied of red wine is a result of a change in market price. Moving from point A to B or C is a movement along the supply curve. The actual supply curve did not change shape, only the market price for red wine changed and thus the quantity supplied by the producers changed.
The dream of spanning the Golden Gate Strait had been around for well over a century before the Golden Gate Bridge opened to traffic on May 28, 1937. Pedestrian Day was held on May 27, 1937. We do not have the exact employment figures. The Bridge was built by 10 different prime contractors and their subcontractors.
To finance the bridge, the Golden Gate Bridge and Highway District was formed in 1928, consisting of San Francisco, Marin, Sonoma, Del Norte, and parts of Mendocino and Napa counties. These counties agreed to collectively take out a large bond, which would then be paid back through bridge tolls.