McDonald Has Invented a Machine That Harvests Corn in the Field,automatically

Multiple Choice

McDonald has invented a machine that harvests corn in the field,automatically shucks the corn from the husk,and peels the kernels from the cob,separating everything for easy disposal or further use.Assuming that all requirements are met for a patent,the length of his patent protection will be

A) 14 years from the completion of the invention.
B) 14 years from the filing of the application with the U.S. Patent and Trade Office.
C) 20 years from the completion of the invention.
D) 20 years from the filing of the application with the U.S. Patent and Trade Office.