The (29) is a general description of the architecture of a workflow management system used by the WFMC, in which the main components and the associated interfaces are summarized. The workflow enactment service is the heart of a workflow system which consists of several (30) 。

30（）

A. workflow engines

B. processes

C. workflow threads

D. tasks

读“大别山山麓与山顶太阳辐射强度及其垂直变化率折线图”，完成下列小题。

有关该地太阳辐射强度的叙述，正确的是（）

A.山麓始终大于山顶

B.山顶始终大于山麓

C.1～8月山麓一直增大

D.9～12月山顶一直减小