Q1: The minimum diameter of sewer to be adopted is

ANS:C - 15 cm

The selection of sewer diameter depends on several factors such as the expected volume of wastewater, the slope of the sewer line, local building codes, regulations, and design standards. While 10 cm is often considered the minimum diameter for sewers in residential or small-scale applications, larger diameters may be required for larger volumes of wastewater or to accommodate future growth and expansion. Choosing a 15 cm diameter for a sewer may be appropriate in situations where there is a moderate volume of wastewater to be conveyed, or where local regulations or design standards specify a minimum diameter greater than 10 cm. This larger diameter provides greater capacity and can help prevent blockages and backups, particularly in areas with higher wastewater flow rates or where there may be a risk of sedimentation or debris accumulation. In summary, selecting a 15 cm diameter for a sewer line strikes a balance between providing sufficient capacity to handle wastewater flow while also being practical and cost-effective for the specific application and local requirements.