The basis of difference between the Parliamentary and Presidential system of government lies in the relation between the legislature and the executive. The Parliamentary system is characterized by a close relationship between the legislature and the executive, where the executive is chosen from and accountable to the legislature. This means that the executive (prime minister) is a member of the legislature and is elected by the majority party or coalition in the legislature. The executive remains in power as long as they maintain the support of the legislature.
On the other hand, the Presidential system separates the executive and legislative branches of government. The executive (president) is elected separately from the legislature and is not directly accountable to it. The president is elected by the people or by an electoral college and has a fixed term in office. The president has significant powers and is not easily removed from office.
The difference in the method of election of the President/Head of the State (option 2) is one of the key features that distinguishes the two systems.
Other options such as the power of judicial review (option 1) and legislative supremacy in law making (option 3) are not as fundamental to the difference between Parliamentary and Presidential systems of government.
Alert - correct answer should be: N/A (the provided answer is correct)