Which of the following is included in forecasting in the demand planning cycle?

Forecasting in the demand planning cycle primarily relies on historical data to predict future demand accurately. Past sales order quantities are crucial because they provide insight into customer buying patterns, seasonality, and trends over time. By analyzing these quantities, businesses can identify whether demand is increasing, decreasing, or remaining consistent. This historical perspective enables planners to make informed decisions about inventory management, production scheduling, and resource allocation.

Market intelligence, while valuable for understanding external factors that may influence demand, such as competitor activity and market trends, does not provide the same direct correlation to previous sales behavior. Past procurement quantities focus more on inventory and supply within the supply chain rather than direct indicators of customer demand. One-off events could disrupt normal demand patterns but do not contribute to a reliable base for forecasting, as they are not consistent or predictable.

Therefore, past sales order quantities serve as a foundational element in demand forecasting, making it the most relevant choice in the context provided.