What is the standard serving size of spirits and liqueurs?

The correct answer is based on the standard serving size commonly recognized for spirits and liqueurs, which is indeed 30 mL, equivalent to 1.5 ounces. This serving size is predominantly used in bars and restaurants as a benchmark for cocktails and other mixed drinks. It aligns with various health guidelines and regulatory recommendations, making it a widely accepted measurement in the industry.

The other choices represent measurements that are either not standard or do not conform to most prevalent serving practices. For instance, 28.5 mL is slightly less than the recognized standard and is not typically used in practice, as most establishments round up to the nearest 30 mL for simplicity and consistency. Similarly, 42 mL represents a larger serving size that exceeds the standard shot measurement, while 25 mL is slightly below the common serving amount. Understanding the conventional serving size is important for ensuring responsible consumption and to meet the expectations of patrons in hospitality settings.