This is an issue of style, structure and modification
A. Because the 2009 swine flu was caused by the H1N1 virus – the same strain of influenza that had caused the massive 1918 flu pandemic – was why researchers were convinced that it had the potential of killing many millions of people, especially children and the elderly. -------
wrong: ‘Because and why’ are redundant
B. Caused by the H1N1 virus, the same strain of influenza that caused the massive 1918 flu pandemic, researchers were convinced that the 2009 swine flu could potentially kill many millions of people, and in particular children and the elderly…….I
mproper modification. The choice says researchers were caused by virus.
C. The H1N1 virus, the same strain of influenza caused the massive flu pandemic of 1918, also caused the 2009 swine flu; therefore, researchers were convinced that it had the potential of killing many millions of people, children and the elderly included. ------
a run-on sentence; the subject H1N1 has two verbs ‘caused Influenza and also caused’.
D. Because the 2009 swine flu was caused by the H1N1 virus – the same strain of influenza that caused the massive flu pandemic of 1918 – researchers were convinced that it had the potential to kill many millions of people, particularly children and the elderly.
Correct choice. The problem of two verbs is overcome by converting the first part into a sub-clause.
E. Researchers were convinced that the 2009 swine flu – which could potentially cause the killing of millions of people, including children and the elderly – was caused by the H1N1 virus, the same strain of influenza that had caused the massive flu pandemic of 1918 -----.
it is improper to use a connective relative pronoun in a parenthetical set up; in addition, ‘potentially cause the killing’ is unduly verbose _________________
Thank you Daagh for your time on GMAT Club and all your contributions! Thank you for everything you did!Your work will remain a great tribute to you here on GMAT Club!
-bb