Which DiffServ marking is the most likely to drop packets?

AF12 has a drop precedence of 2, which is lower than AF13's drop precedence of 3, making it less likely to be dropped.

AF32 has a drop precedence of 2; the '3' denotes the class, not the drop precedence, and thus it is less likely to be dropped than AF13.

In DiffServ Assured Forwarding (AF) markings, the format AFxy indicates the AF class (x) and the drop precedence (y). A higher 'y' value signifies a higher drop precedence, meaning packets with AF13 have the highest drop precedence (3) among the given options, making them the most likely to be dropped during network congestion compared to AF11 (drop precedence 1), AF12 (drop precedence 2), or AF32 (drop precedence 2).

AF11 has a drop precedence of 1, which is the lowest among the options, making it the least likely to be dropped under congestion.