differential leveling between benchmarks A,B,C,D, and A gives elevation differences(m) of -15.632, 32.458, 38.214, and -55.025, and distances(km) of 4,6,5, and 3 respectively. If the elevation of A is 634.597m, what are the adjusted elevations for benchmarks B, C and D? What is the order and class of the leveling?