What is one factor that can increase a criminal sentence for career offenders?

One factor that can significantly increase a criminal sentence for career offenders is having more than four prior felony convictions. This element is particularly relevant because the legal system often enforces stricter penalties for individuals who have a history of repeated criminal behavior. Career offenders, by definition, are individuals who have been convicted of multiple felonies and therefore may pose a greater risk to public safety. The rationale behind this approach is to deter repeat offenses, ensuring that those who have shown a pattern of criminal activity are subject to enhanced sentencing. This increased severity reflects the justice system's goal to reduce recidivism and protect the community from individuals with established histories of felonious conduct.

Other factors, while they may have an influence, such as the offender's age or the nature of the criminal conduct, do not have the same straightforward impact on sentence enhancement as the number of prior felony convictions does. Moreover, plea bargains often lead to reduced sentences rather than increased ones, which further distinguishes the correct answer in context.