Which of the Following Has NOT Generally Been Found in Research

Which of the following has NOT generally been found in research on parole release?

A) inmates released from prison on parole for the first time are more likely to succeed than re-releases
B) state inmates released through mandatory parole almost always have a higher success rate than inmates released by a parole board
C) the chances of failure are generally highest during the early stages of parole
D) all of the choices have been found