In the case in the text, Paramount Communications, Inc. v. Time, Inc., what rule expansion did the Supreme Court of Delaware create?

a. A board may oppose a hostile takeover as long as it had a preexisting, deliberately conceived corporate plan justifying its opposition.

b. A board may oppose a hostile takeover when there is a "better deal."

c. A board may oppose a hostile takeover as long as the defensive measure adopted was reasonable in relation to the threat posed.

d. A board may oppose a hostile takeover as long as it has reasonable grounds for believing that a danger to corporate policy and effectiveness existed.