In the sentence "The cost of launching Operation Columbus is a staggering US' 5 million "( paragraph 3), the word "staggering" has the meaning of _____.

A．boost Americans' confidence in their art.
B．follow the pattern set by his Italian edition.
C．help Italians understand American art better.
D．expand the readership of his magazine.

A．they both benefited from Italian sponsors.
B．they were explorers in their own ways.
C．they obtained overseas sponsorship.
D．they got a warm reception in America.