Option D is correct because the context clearly states that 'the most important feature of parliamentary executive is that the executive is routinely under the control and supervision of the legislature.' It further mentions that 'The Council of Ministers is collectively responsible to the Lok Sabha.' This means the executive must maintain the confidence and support of the majority in the parliament to remain in power. Option A is incorrect because merely having a parliament does not define a parliamentary executive. Option B is incorrect because the executive is not directly elected by the parliament. Option C is incorrect because the parliament and executive are separate organs with distinct functions—the parliament does not function as the Executive.