Object-oriented analysis(OOA)is a semiformal specification technique for the object-oriented paradigm. Object-oriented analysis consists of three steps. The first step is (71) . It determines how the various results are computed by the product and presents this information in the form of a (72) and associated scenarios. The second is (73) ，which determines the classes and their attributes. Then determine the interrelationships and interaction among the classes. The last step is (74) , which determines the actions performed by or to each class or subclass and presents this information in the form of (75) .

75（）

A．activity diagram

B．component diagram

C．sequence diagram

D．state diagram

幸福感是人们对生活满意程度的一种心理体验，它以一定的物质财富为基础，但在现实生活中，幸福感的提升与物质财富的增加并不一定同步。这说明（）

①社会存在决定社会意识

②社会意识具有相对独立性

③社会意识对社会存在具有促进作用

④社会意识的变化独立于社会存在的变化

A.①②

B.②③

C.①④

D.③④