Pick up the correct statement from the following: A. The full supply level of a canal should be above ground level B. According to Lacey, regime conditions require a particular slope for a given discharge and silt factor C. In case the ground slope is less than the required bed slope, the silt factor must be reduced by permitting the entry of coarse silt D. All the above

The correct answer is D. All the above.

A. The full supply level of a canal should be above ground level. This is to ensure that the canal is always full and that there is no risk of the water level dropping below the required level.

B. According to Lacey, regime conditions require a particular slope for a given discharge and silt factor. This means that the slope of the canal bed must be in a certain range in order to ensure that the canal is stable and that the water flows smoothly.

C. In case the ground slope is less than the required bed slope, the silt factor must be reduced by permitting the entry of coarse silt. This is to ensure that the canal bed is still stable even though the slope is not ideal.

D. All the above.