Concept:The main difference between presidential and parliamentary systems lies in how executive power is held and for how long.
Explanation:In a presidential system, executive power is vested in a single individual, the president.
The president is elected separately from the legislature and serves a fixed, limited tenure.
In a parliamentary system, the executive is drawn from the legislature and depends on its confidence.
The prime minister and cabinet remain in office only as long as they enjoy parliamentary support.
Thus, the key distinguishing feature is that the president’s tenure in office is constitutionally limited.
Answer:D. The tenure of office of the president is limited.