Donald Trump and global crude producers are set to take prices on a bumpy ride this year, according to the world’s biggest independent oil trader. As investors are kept on tenterhooks over U.S. policies and whether OPEC and other nations will curb output as pledged, global benchmark Brent crude may vacillate between $52 and $62 a barrel, according to Kho Hui Meng, the head of the Asian arm of Vitol Group.