ANS:B - 2.0

The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter typically falls within the range of 2.0. This ratio represents the peak flow compared to the average flow in sewer mains. It's important to consider the variations in sewage flow throughout the day and year. The maximum flow usually occurs during peak periods, such as mornings or evenings when people are using water more extensively (e.g., showering, cooking, etc.). The average flow accounts for the typical flow rate over a longer period, which includes both peak and off-peak times. The ratio of 2.0 indicates that the maximum flow can be twice the average flow in sewer mains up to 1 m in diameter. This factor helps in designing sewer systems to accommodate peak flows without causing overflows or backups.