EXAMPLE : A majority of the international journalists ...

 A majority of the international journalists surveyed view nuclear power stations as unsafe at present but that they will, or could, be made sufficiently safe in the future. 
(D) think that they will be or could 
(E) think the power stations would or could 

Ah, yes, I can see where you're coming from here: you don't like 'they' here. Neither do I, at least for GMAT purposes (meaning I wouldn't object to this sentence if I read it in a newspaper, but I know that the GMAT writers would ax it): 'they' could, technically, refer either to the power stations or to the journalists. 

BUT - choice E misuses 'would,' which is a past-tense construction. 
Correct: The journalists THOUGHT that the plants WOULD be made safe in the future. 
Correct: The journalists THINK that the plants WILL be made safe in the future. 
Incorrect: *The journalists THOUGHT that the plants WILL be made safe in the future.

Notes

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