Short Answer: The first three are absolutely true. Congruency is maintained if all you are doing is shifting the figure 8 spaces away. Since the figures are congruent, their corresponding parts are equal and the statements made are always true. That's the guiding principle.
A is true. See the short answer.
B is True. You have gone 8 units away. The distance between the old G and the new one is 8 units. This is not a congruency property but it is true because it is given. You haven't altered the shape or rotatated it.
C is true by conguency. You have just shifted things 8 units. You have maintained equality and you have maintained distance between corresponding parts.
That leaves D. If the figures are regular, that will be true. If they are not regular, non corresponding external angles cannot be guaranteed to be true.
