Final answer:
A firm uses both trend projection and seasonal factors to simulate sales by considering long-term trends and short-term seasonal variations.
Step-by-step explanation:
A firm uses both trend projection and seasonal factors to simulate sales for a given time period. This means that the firm considers both long-term trends in sales as well as short-term seasonal variations. By using trend projection, the firm can estimate how sales will change over time based on historical data, while seasonal factors help to account for regular patterns or fluctuations in sales that occur during specific times of the year.
Therefore, the correct answer to the question is c) To both trends and seasonal factors.