单选题 One tool that is useful during both analysis and design is the ______, which is a pictorial representation of the items of information (entities) within the system and the relationships between these pieces of information.
【正确答案】 D
【答案解析】[解析] 在系统分析和设计中同样适用的工具是答案D实体关系图，它通过图形形式，表现系统内的实体信息以及这些信息之间的关系。