讨论一道奇怪的题。

In the rectangular coordinate system,
points (4, 0) and (– 4, 0) both lie on circle C.  What is the maximum possible value of the
radius of C ?

A.        2

B.        4

C.        8

D.     16

E.      There is no finite maximum value.

哪位好心人能帮忙翻译一下。