Answer:
The correct option is B. semantics.
Step-by-step explanation:
If the teacher and students are discussing what the words "nice" and "awful" used to mean, they are most likely discussing semantics.
Semantics is a branch of linguistics concerned with the study of meaning, be it of a word, a phrase, a sentence, or a text. It presents a variety of subbranches, but two of the most well-known subbranches are logical semantics and lexical semantics. Logical semantics studies the logical aspects of meaning, such as sense, implication and reference. Lexical semantics, on the other hand, studies the meanings of words and the relationship between words.