(B) Context-dependent meaning
The word "red" here means anger, not a colour. Its meaning changes based on context, which is a key characteristic of natural language.
The source passage directly uses a similar example — "His face turned red after he found out..." — to illustrate that the word "red" can mean shame, anger, or a physical reaction depending on context. Examiners expect students to identify this as context-dependent meaning. The other options (redundancy, grammatical structure, temporal change) are also features of natural language but do not apply here.