Extracted text: 2. In general multi-storey building of frame structure, the beams and columns are rigidly connected with cast-in-place floor. Which one of the following statements about the calculation length of each column is correct? A. l6=1.0H, for bottom column, lo=1.25H, for the remaining columns B. lo=1.25H, for bottom column, lo=1.5Hc for the remaining columns C. lo=1.0H, for bottom column, lo=1.0H for the remaining columns D. l6=1.25H, for bottom column, lo=1.25H, for the remaining columns