Final answer:
Mrs. Caroline developed her education techniques on her own, leveraging her extensive training and studious habits reflected by feedback on her character and abilities.The correct option is D.
Step-by-step explanation:
The student is asking about the education techniques of Mrs. Caroline. Based on the provided information, Mrs. Caroline was one of the best students throughout her course and graduated with broad and thorough training. It is evident that Mrs. Caroline was well educated and equipped with good ability, studious habits, and a very fine character. As the information praises her character and education, it suggests that Mrs. Caroline developed her education techniques on her own, combining her studious nature with the broad training she received.