The correct option is
A They felt this led to more crime as criminals learned from each other
A separate system is a form of prison management based on the principle of keeping prisoners in solitary confinement. When first introduced in the early 19th century, the objective of such a prison or "penitentiary" was that of penance by the prisoners through silent reflection upon their crimes and behavior, as much as that of prison security. More commonly, however, the term "separate system" is used to refer to a specific type of prison architecture built to support such a system. The Penitentiary Act which passed in 1779 following John Howard's agitation introduced solitary confinement, religious instruction, and a labor regime and proposed two state penitentiaries, one for men and one for women. Designers of these penal institutions drew heavily on monastic solitary confinement to both destroy the identity of the inmate (and thus make him easier to control) and to crush the "criminal subculture" that flourished in densely populated prisons.
Prisoners incarcerated in separate system prisons were reduced to numbers, their names, faces, and past histories eliminated. The guards and warders charged with overseeing these prisoners knew neither their names nor their crimes and were prohibited from speaking to them. Prisoners were hooded upon exiting a cell and even wore felted shoes to muffle their footsteps. The result was dumb obedience and passive disorientation that shattered the "criminal community." Hence, Option A is correct. Among the rest, escape from prisons(prison break) or prison riot was possible only if the prisoners mixed together, and was not desirable to the reformers, hence, incorrect.