She couldn’t believe that her son had behaved _____ to be disciplined by the teacher.a.worse thanb.as bad asc.badly enoughd.worse than

To fill in the blank in the sentence "She couldn’t believe that her son had behaved _____ to be disciplined by the teacher," we need to consider the grammatical correctness of each option provided.

Option Analysis

1. a. worse than - This phrase typically compares two things but is not a complete thought in this context.
2. b. as bad as - This phrase implies equality in the comparison but does not specify that the behavior warranted discipline.
3. c. badly enough - This phrase suggests that the son's behavior was sufficient to warrant discipline, making it a strong candidate.
4. d. worse than - Like option a, this suggests a comparison, which is not fitting because there's no second behavior to compare to.

Conclusion

The best choice that fits the sentence grammatically and contextually is c. badly enough. This indicates that her son’s behavior was sufficiently problematic to merit the teacher's disciplinary action.

Final Answer

The correct choice to complete the sentence is c. badly enough.