A Parliamentary System of Government is one in which

The correct option is: the Government is responsible to the Parliament and can be removed by it.

To understand why this is the defining feature of a Parliamentary System of Government, we can break down its core principles:
1. Executive Responsibility: In a parliamentary system, the executive branch (the Government, led by the Prime Minister) is not independent of the legislature (the Parliament). Instead, the Government is drawn from and remains directly responsible to the Parliament.
2. Collective Responsibility: The council of ministers holds office only as long as they command the confidence of the majority in the legislature (specifically the lower house of Parliament). If the Parliament loses confidence in the ruling government, it can pass a "No-Confidence Motion".
3. Removal Power: The passage of a No-Confidence Motion obligates the Prime Minister and their cabinet to resign, thereby removing the Government from power before the completion of its nominal term. This ensures continuous accountability of the executive to the representatives of the people.

Let's briefly see why the other options do not define a parliamentary system:
- Representation of all parties: Governments are typically formed by the majority party or a coalition, not all parties in Parliament.
- Removal by the people: Direct removal of the government by the electorate is a feature of direct democracy mechanisms (like recall), not standard parliamentary representative systems where the removal is mediated by the Parliament.
- Fixed term without removal: A system where the executive cannot be removed by the legislature before a fixed term is characteristic of a Presidential System (e.g., the United States), not a Parliamentary System.