设 13101 班学生的关系为 R , 13102 班学生的关系为 S ,校文艺队学生的关系为 T ,分别如图 10-3 (a) 、 (b) 与 (c) 所示,关系 R 、关系 S 、关系 T 都是由学号、姓名、年龄三个属性组成,且相应的属性取自同一类型数据。根据以上关系回答问题: 关系 R 和关系 T 的 “ 差 ” 操作的结果是 _____ 。
【单选题】What is a Profit Entrepreneurship is directly responsible for production. The business person (entrepreneur) takes a cue from consumers in deciding what they want or. in the case of a new product,____...
A.
what profit really means
B.
it is too large and represents too much of the consumer's dollar
C.
whether they come from outside the business
D.
as the difference between total revenue and total cost
E.
what the business person has left after paying expenses