食用农产品价格上涨，原因是多方面的。流通环节过多，成本加大是价格上涨的一个重要推手。这表明(　　)

A．质量决定价格

B．供求影响价格

C．流通环节决定价格

D．价值决定价格

--- Jack, what about the lecture?

--- It is the most inspiring lecture that I _________ since I came to this university.

A．attended

B．have attended

C．am attending

D．had attended