Answer from cs61c-eo (James McBryan 16730959) for Question 3
the X's mean that it does not matter what those values are if a is 0 that means o will be 1 no matter what.  If a is 1 and c is 0 then o is 1 and  if as 1 and c is 1 then o is 0.  The outputs totally do not matter upon b and yes the table is satisfie