将等物质的量的F₂和ClF混合，在密闭容器中发生反应：F₂(g)+ClF(g)ClF₃(g)；△H<0。下列叙述中正确的是 [ ]

A．恒温恒容，当ClF 转化40% 时，容器内的压强为初始时的0．8 倍

B．若c(F₂):c(ClF): c(ClF₃) =1: 1: 1， 则反应一定达到平衡状态

C．达到平衡后，若增大容器体积，则正反应速率减小，逆反应速率增大，平衡左移

D．平衡后再降低温度，保持恒容，达到新的平衡，则混合气体的平均摩尔质量减小

Darth Corporation’s most recent income statement shows net sales of $ 6000, and Darth’s marginal tax rate is 40 percent. The total expenses reported were $ 3200, all of which were paid in cash. In addition, depreciation expense was reported at $ 800. A further examination of the most recent balance sheets reveals that accounts receivable during that period increased by $1000. The cash flow from operating activities reported by Darth should be:

A．

B．

C．