The correct option is D Fortunately, out of hundreds of planes flying to international destinations only two were shipwrecked last year.
Since the word "fortunately " modifies the word "planes" these should be placed close, but not together so as to retain the subject-verb agreement. Hence Option C is correct. The rest of the options do not place the qualifying adverb close to the subject or do not retain the subject-verb agreement, hence these are incorrect.