Final answer:
The incorrect statement about parliamentary democracy is that voters elect both the legislature and head executive; in reality, the prime minister is chosen by the majority in parliament, not directly by the voters.
Step-by-step explanation:
The statement about parliamentary democracy that is NOT true is c) Voters elect both the legislature and head executive. In a parliamentary system, voters elect their legislature, but it is the majority party or coalition in the parliament that chooses the prime minister, who serves as the head of government.
The prime minister may be the political head of state in some countries, but they are primarily the leader of the government and are selected by their peers within the elected legislative body, not directly by the public.
It is in a presidential-parliamentary system where voters elect both a president and a parliament, with the parliament also choosing a prime minister.