So far no life has been found outside the earth, but while some scientists are actively searching for living things in outer space, others firmly believe there ____ .

A．mustn’t be

B．may not be

C．can’t be

D．won’t be

下列不符合协议抵债条件的是（）。

A.我行设定的抵质押无效

B.我行债权未设定抵质押

C.我行的抵质押物存在多个抵质押权人的

D.我行设定的抵质押不足值