问题
单项选择题
If 4 and 11 are the lengths of two sides of a triangular region, which of the following can be the length of the third side ？（）
Ⅰ.5
Ⅱ. 13
Ⅲ. 15
A. Ⅰ only
B. Ⅱ only
C. Ⅰ and Ⅱ only
D. Ⅱ and Ⅲ only
E. Ⅰ, Ⅱ, and Ⅲ
答案
参考答案：B
解析：
A leg of a triangle cannot be greater than or equal to the sum of the other two legs. This principle eliminates both Ⅰ (11＞5+4) and Ⅲ (4+11=15). Therefore, Ⅱ is the only acceptable length.