Answer
(a) none.
(b) Alaska and Southwest airlines.
Work Step by Step
(a) Add up the three dimensions, we have $9+12+21=42\ in$. Compare with the numbers in the table, we can see that all airlines will allow it as a carry-on. In other words, there is no airline that would not allow it as a carry-on.
(b) Add up the three dimensions, we have $10+14+22=46\ in$. Compare with the numbers in the table, we can see that Alaska and Southwest airlines will allow it as a carry-on.
