If the size of a column is reduced above the floor, the main bars of the columns, are

ANS:D - all the above.

When the size of a column is reduced above the floor level, it often requires a transition in the reinforcement arrangement to accommodate the change in dimensions. This transition typically involves adjustments to the main reinforcement bars of the column. Here's what typically happens:

1. Continued Up: In some cases, the main reinforcement bars of the column are continued up without any interruption. This is often the case if the reduction in size is gradual and does not significantly affect the structural integrity or load-carrying capacity of the column.
2. Bent Inward at the Floor Level: If the reduction in size is abrupt and significant, the main reinforcement bars may need to be bent inward at the floor level to fit within the reduced dimensions of the column. This bending ensures that the bars maintain proper cover and spacing within the concrete.
3. Stopped Just Below the Floor Level and Separate Lap Bars Provided: Alternatively, the main reinforcement bars may be stopped just below the floor level where the reduction in size occurs. In this case, separate lap bars are provided to connect the main bars of the column below and above the floor level. This approach ensures proper development length and adequate bond between the bars.

Therefore, the correct answer is: All of the above.All of the above. Depending on the specific design requirements and construction constraints, any of these approaches may be adopted to accommodate the reduction in size of the column above the floor level.