30. The diagram shown the electric field lines in a region of space containing two small charged spheres (Y and Z). Then: 

(A) Y is negative and Z is positive
(B) the magnitude of E is the same everywhere
(C) the field is strongest midway between X and Y
(D) a small negatively charged body placed at X would be pushed to the right

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統計： A(1), B(0), C(1), D(9), E(0) #874933