The Logic: Cause and Effect
The sentence discusses the deterrent effect of legal punishment-the idea that people won't commit crimes because they fear the consequences.
- The Condition: The deterrent effect "ceases" (stops working).
- The Cause: Something is happening to the punishment "frequently."
- The Prediction: If people see that others are breaking the law but not actually facing the mandated punishment, they will stop fearing the law. We are looking for words that mean the punishment was canceled, reduced, or bypassed.

The Correct Answers:
C. waived
E. commuted
- Why they work: To waive a punishment means to refrain from enforcing it. To commute a punishment (in a legal sense) means to reduce a judicial sentence to a less severe one (e.g., commuting a death sentence to life in prison). In both cases, the "threat" of the original law is removed or lessened, which destroys its ability to deter others.

Why the others fail:
- A. arbitrary: While frequent arbitrary (random) punishment is bad for justice, it might actually increase fear/deterrence rather than cease it.
- B. changed: This is too vague. A change could make a punishment harsher, which would likely increase deterrence.
- D. lenient: This is a strong "trap" word. While lenient punishments are less of a deterrent, "waived" and "commuted" are better synonyms for each other in a legal context regarding the removal of a set penalty.
- F. applied: If punishment is frequently applied, the deterrent effect should technically be stronger, not weaker.

Final Completed Sentence
Punishment for transgressions of the law ceases to have a deterrent effect if the punishment is frequently waived / commuted.