Which of the following, if true, would cast most doubt on the conclusions drawn from Head's higher-resolution models

A．TheresultsofgeographicalsurveyprovethatnocraterlargerthantwelvekilometersexistsonthesurfaceofMars.
B．FragmentsfromsmallerimpacteventsonMarsarehighlyunlikelytosurviveentrythroughtheEarth'satmosphere.
C．ThevelocityofrocksescapingfromMar'sgravityisgreaterwhentheyhavebeenloosenedbyalargeimpact.
D．HugeimpactsonMarsareproventobelessrarethanwaspreviouslythought.
E．Adouble-successionoflargeimpactsisfoundtohaveoccurredonMarsinarelativelyshortperiodoftime.