Which of the Following Is True Within Exchange Economies

Which of the following is true within exchange economies:

A) All efficient allocations lie in the set of core allocations.
B) All core allocations are efficient.
C) The set of efficient allocations can be defined without knowing individual endowments.
D) (a) and (b) are true.
E) (a) and (c) are true.
F) (b) and (c) are true.
G) All of the above are true.
H) None of the above are true.