The word "tenuous" in the last paragraph means ______.

A．the U.S. economy has tumbled
B．more people donated for people affected by Sept. 11 attacks
C．more people stopped donating since they found the donations were misused
D．both A and B

A．nuclear war will definitely not take place
B．international agreements are now reached more and more easily
C．man is beginning to realize that nuclear war is his greatest enemy
D．world opinion is in favor of nuclear war