The central feature of Polyarchy is a system of government where power is in the hands of elected officials. This means that option 1 is a central feature of Polyarchy.

Option 2 states that the right to run for office is restricted. In a Polyarchy system, there is no restriction on the right to run for office. Therefore, option 2 is NOT a central feature of Polyarchy.

Option 3 states that practically all adults have the right to vote. In a Polyarchy system, the right to vote is generally extended to all adults. This makes option 3 a central feature of Polyarchy.

Option 4 states that there is free expression and a right to criticize and protest. Free expression, criticism, and the right to protest are important aspects of a Polyarchy system. Therefore, option 4 is also a central feature of Polyarchy.

In conclusion, the only option that is NOT a central feature of Polyarchy is option 2, which states that the right to run for office is restricted.