（文）等差数列{a_n}公差不为零，首项a₁=1，a₁，a₂，a₅是等比数列，则数列{a_n}的前10项和是（　　）

A．90

B．100

C．145

D．190

You have been given a high priority task that needs to be completed within a short time frame．Since you know what has to be done，you assign tasks to the different team members and tell them when and how the tasks should be done．The management style that you are following is （）.

A．directing

B．laissez faire

C．delegating

D．task-oriented