The IETF (Internet Engineering Task Force) is responsible for developing and overseeing internet standards. Which of the following is not a common protocol maintained by the IETF?

1. Correct Answer
   Incorrect Answer
   a

   Hypertext Transfer Protocol (HTTP)

2. Correct Answer
   Incorrect Answer
   b

   Internet Protocol (IP)

3. Correct Answer
   Incorrect Answer
   c

   Global Positioning System (GPS)

4. Correct Answer
   Incorrect Answer
   d

   Simple Mail Transfer Protocol (SMTP)