Assume that all sewer piping is installed at a slope of 1/4 inch per foot Based upon drainage fixture units

While a 4-inch pipe may be suitable for certain applications, it does not necessarily meet the minimum requirement for section D, depending on the drainage fixture units calculated. If the total fixture units exceed the capacity of a 4-inch pipe, it would not be adequate for proper drainage.

A 5-inch pipe could potentially accommodate more drainage than a 4-inch pipe, but it may still fall short of the minimum size required for section D, depending on the fixture units involved. The choice of pipe diameter must be determined by specific calculations related to drainage demands.

A 6-inch pipe offers a larger diameter that may exceed the minimum requirement for drainage in section D. However, unless specifically calculated based on the drainage fixture units, it cannot be assumed that this is the minimum size necessary, as larger pipes are often used for increased capacity but may not be necessary for all installations.

An 8-inch pipe is significantly larger than the minimum needed and would generally exceed the requirements for section D. While it provides ample capacity for drainage, it is not the minimum size needed, leading to potential waste in material costs and space.