正确求解这道题目，要求选择针对初中学生最合适的解法。
要循序渐进，并且在合适时机讲解题目中涉及到的**知识点**，视频要1分钟以上，画图时不要有偏差，要精确，动画越生动活泼越好，不要大量堆叠文字。
编排策略如下（仅供参考，不一定全部按照这个来，根据你的经验即可）：
"第一幕 - 设置": {
"时长": "20%",
"内容": "题目展示、概念回顾、学习目标",
"视觉策略": "静态文本 + 简单图形"
},
"第二幕 - 冲突": {
"时长": "60%",
"内容": "问题分析、逐步求解、知识应用",
"视觉策略": "动态构建 + 高亮显示 + 分步演示"
},
"第三幕 - 解决": {
"时长": "20%",
"内容": "答案验证、知识总结、拓展思考",
"视觉策略": "结果展示 + 知识网络"
}---**Question Number:** 5
**Question Stem:**
如图，DE 是△ ABC 的中位线，∠ ABC 的角平分线交 DE 于点 F，AB = 6，BC = 9，则 EF 的长为
**Options:**
A. 0.5
B. 1
C. 1.5
D. 2
**Chart/Diagram Description:**
* **Type:** Geometric figure (triangle with internal line segments).
* **Main Elements:**
* A triangle ABC.
* Points D on side AB, E on side AC, and F on line segment DE.
* A line segment DE connecting sides AB and AC.
* A line segment BF starting from vertex B and intersecting DE at F. BF is the angle bisector of ∠ABC.
* **Relationships:**
* DE is the midline of △ABC, meaning D is the midpoint of AB and E is the midpoint of AC, and DE is parallel to BC.
* BF is the angle bisector of ∠ABC.
* F is the intersection point of BF and DE.
* **Labels:** Points A, B, C, D, E, F are labeled.
* **Given Lengths (from question stem):** AB = 6, BC = 9.