GMAT Sentence Correction (SC) | Re: In 1974 a large area of the surface of Mercury was photographed from

I have a simple explanation.
If you look at the original sentence and concentrate on its meaning--- It says Nothing about the 'purpose' of the 'Photograph' being taken.
The Result just happened simultaneously
Whereas For B-- The Result of 'finding the similarity in craters' is because of deliberately 'Photographing'
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