Suppose the President Suffers a Serious Illness and Is Unable

Suppose the president suffers a serious illness and is unable to fulfill the duties of the office.What happens then?

A) Either the president or the vice president and cabinet together declare the president disabled,and the vice president becomes acting president.
B) The president's spouse becomes acting president.
C) Congress appoints an acting president to serve until the president is able to resume the duties of office.
D) The Constitution makes no provision for such an event.
E) The Senate appoints a temporary president.