A computer equipped with signature-recognition software, which restricts access to a computer to those people whose signatures are on file, identifies a person' s signature by analyzing not only the form of the signature but also such characteristics as pen pressure and signing speed. Even the most adept forgers cannot duplicate all of the characteristics the program analyzes. Which of the following can be logically concluded from the passage above? ['Signature-recognition software has taken many years to develop and perfect.', 'The time it takes to record and analyze a signature makes the software impractical for everyday use.', 'In many cases even authorized users are denied legitimate access to computers equipped with the software.', 'Nobody can gain access to a computer equipped with the software solely by virtue of skill at forging signatures.']