What is a key feature of a scalene triangle?

A scalene triangle is defined by having all sides of unequal lengths. This characteristic is what distinguishes scalene triangles from other types, such as isosceles triangles, which have two equal sides, and equilateral triangles, where all three sides are equal. Since the definition of a scalene triangle specifically includes that no two sides are the same length, choice B accurately represents this property.

In addition, other features mentioned in the other options do not apply to scalene triangles. For instance, having two equal sides (the first option) would categorize a triangle as isosceles, while having all angles equal (the third option) would classify it as equilateral. The last option, which refers to having one right angle, relates to right triangles but does not define a scalene triangle. Hence, the standout feature that all sides are unequal uniquely identifies scalene triangles, making choice B the correct one.