Answer:
d. represented by the meaning that dictionary entries afford for linguistic forms.
Explanation:
In philosophy, the word proposition can have linguistic and non-linguistic meanings. In our daily use of the word "proposition", it has a linguistic connotation as it refers to a statement which could either be true or false. They are sharable objects and therefore, exclude personal thoughts and utterances that are not sharable.
Its non-linguistic usage is applied in technical philosophic terms. The word can be used in declarative statements and to also express belief in something.