The departmental stores work— eight to seven:

This question tests the correct usage of prepositions to indicate a time range or interval. Choosing the appropriate preposition is essential for clear and grammatically correct communication.

• The preposition "between" is used to specify a range or interval with two distinct endpoints. In the phrase "between eight and seven," it correctly indicates that the departmental stores operate within the period starting at eight (e.g., 8 AM) and ending at seven (e.g., 7 PM).
• Option B, "by," indicates a deadline or a means, not a range (e.g., "by seven o'clock").
• Option C, "during," indicates a period of time but doesn't typically specify a range with two distinct numerical endpoints in this manner (e.g., "during the day").
• Option D, "none," is incorrect because "between" is the grammatically correct and most appropriate choice.

Correct preposition usage is vital for precise language.