I’d say # 1 since all other sentences support this point
If a proposition is true, then we say it has a truth value of "true"; if a proposition is false, its truth value is "false". For example, "Grass is green", and "2 + 5 = 5" are propositions.
hope this helps :)
Number three is the answer
In fiction, you would like to give variety to your word choices. In formal business or academic writing, You want to prevent ambiguity and so may use the same word again and again to make your meaning clear. For example "contract" might be used repeatedly rather than along with some synonyms for it.
