单项选择题

When John Jacob Raskob purchased a site for the skyscraper, he

A.began to build a monumental building together with Walter Chrysler.
B.joined in the construction of a tall building along with Walter Chrysler.
C.kept a secret of his own skyscraper while he joined Walter Chrysler.
D.did not know how taller his building would be than Walter Chrysler's.