Select from options: Continue writing the next sentence.

How to buy a carry on bag 
Look up your airline's size restrictions. 
Most airlines restrict total bag size to 45 inches (114.3 cm). This breaks down to about 22 inches (55 cm) long , 14 inches (35 cm) wide, and 9 inches (22 cm) deep.

Pick from:
(I). Don't buy this bag if you have concerns or feels about having too many things to carry, such as mp3 players, headphones, etc. If at any time you are at major airports or hotels, talk to your flight attendant to find out about restrictions on what bag sizes are allowed.
(II). Many airlines also prohibit the bag limit among passengers who fly in lower-class levels of the airport. The airline's recommended rating for bags beyond a few miles or miles is incredibly variable and will often tell you whether or not to order the bags you're looking for.
(III). Airlines include this restriction, but it is still not shared by other airline companies such as the american airlines. Airlines using luggage exclusion generally agree that many bags cannot come with a spacer, including non-mesh-sided suitcases.
(IV). If you know what airline you will be flying most frequently, visit their website to see if their restrictions vary from the standard. Some international carriers only allow a length of 20 inches (50 cm), so keep that in mind if you fly a variety of airlines internationally.
Answer:
(IV).