Which statement about the preliminary design stage of a software development project is true ______

A．The preliminary design is an internal document used only by programmers

B．The preliminary design is the result of mapping product requirements info software and hardware functions

C．The preliminary design of the product comes from the requirement specification

D．The developers produce the preliminary design by defining the software structure in enough detail to permit coding

若日极值出现时间恰为24时，对于辐射极值，一律记录为24时00分，其它要素记录24时00分和00时00分均可。