Which Statement Strongly Supports Incurring the Expense of Having a Patent

Which statement strongly supports incurring the expense of having a patent agent search relevant literature for the purposes of establishing novelty?

A) Ninety percent of all patents are for improvements to existing patented inventions.
B) The opinion is required to establish both ingenuity and inventiveness.
C) Opinions are crucial to the grace period for filing the patent application.
D) The date of earliest use becomes the disclosure date used for establishing novelty.