To answer the first question look at the difference between the air temperature and the dew point temperature.  The larger the difference the lower the relative humidity (the RH=100% if there is zero difference).  There is a 40 F difference in A and a 30 F difference in B.  City B has the higher relative humidity.

The saturation mixing ratio value depends on air temperature.  City A has a higher air temperature and therefore a higher saturation mixing ratio value.

The mixing ratio tells you how much water vapor is actually in the air.  Mixing ratio values aren't given here, but we do have the dew point which is almost the same thing.  The city with the higher dew point temperature will have the highest actual amount of water vapor.  That is City A.  Note that City B has a higher relative humidity but actually contains less water vapor than City A.