GMAT Sentence Correction (SC) | Re: NASAs methodical approach to the exploration of Mars has not

NASA’s methodical approach to the exploration of Mars has not yet answered the questions of whether biological life forms ever emerged on Marsand whether, presuming such life forms having left fossil traces to begin with, those traces can still exist in some moist recesses of the cold and arid planet.



A.and whether, presuming such life forms having left fossil traces to begin with, those traces can
B.and whether, if it is presumed that such life forms left some fossil traces to begin with,