Continuing from the previous question using the symmetry-integration diagram. From 1913 to 1939, world trade flows collapsed, falling in half relative to GDP, from about 20% back to 10%. Many economic historians think this was driven by exogenous increases in transaction costs from rising transport costs and increases in tariffs and quotas. How would you depict this shift for a pair of countries in the symmetry-integration diagram that started off just above the FIX line in 1913? Use the letter B to label your starting point in 1913 and use C to label the end point in 1939