Which of These Is NOT a Legitimate Reason to Believe

Which of these is NOT a legitimate reason to believe that the northern hemisphere of Mars has experienced more geologic activity than the southern hemisphere?

A) Most of the Martian craters are in the southern hemisphere.
B) Most of the Martian volcanoes are in the northern hemisphere.
C) The Martian magnetic field is oriented north to south, opposite Earth's magnetic field.
D) The southern hemisphere has a higher elevation than the northern hemisphere.