【单选题】

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.