Beginning in the 3rd century rome was developing a “soft belly” what does that mean

Based on the given line above which is Rome was developing a "soft belly" beginning in the 3rd century, this means that the Romans became lazy. On the other hand, "soft belly" also means having a harsh time or problems. During this time, The Romans become lazy and that was one of the reasons for the fall of Rome.

Icould be wrong but i would say b.