Consumers are getting more sensible and buy only     they need in spite of all the advertisements they see.

A．that

B．what

C．which

D．whether

用一根钢绳起吊一个沉水底的实心铜质文物，文物未露出水面时，钢绳受到的拉力为7.9×10³牛，若钢绳能承受的最大拉力是10⁴牛，能否用此钢绳将文物吊出水面？（P铜=8.9×10³千克/米³，g取10牛/千克）