等比数列{a_n}的前n项和为S_n，a₁=1，若4a₁，2a₂，a₃成等差数列，则S₄=  [ ]

A．7

B．8

C．16

D．15

—Do you know        the price of the TV set is?            

—I don't know, but I think the price must be very         .          [ ]

A. how much, expensive              

B. what, high          

C. what, expensive             

D. how much, high