Here are some synonyms for the words you mentioned:
Synonyms for "couplet": pair, duo, twosome, duet, brace.
To find synonyms for words, you can use a thesaurus. There are many online thesaurus websites or you can also use a physical thesaurus book. You can search for the word you want to find synonyms for, and it will provide you with a list of words or phrases that have similar meaning.
Synonyms for "denotation": meaning, definition, signification, sense.
Synonyms for "details": specifics, particulars, elements, facts.
Synonyms for "devices": techniques, methods, strategies, approaches.
Synonyms for "dialect": vernacular, language, jargon, idiom.
Regarding the second set of words you provided, those are not synonyms, but rather a list of unrelated words. If you are looking for synonyms or antonyms for those words, you can follow the same process of using a thesaurus.
For the word "gourmen", it seems to be misspelled. If you meant "gourmet", then a possible synonym for it would be "foodie".
For the second question, the correct answer is "a). biologist:scientist". A biologist is a specific type of scientist who studies living organisms. The other options listed are not direct synonyms or similar relationships.
I hope this helps! If you have any further questions or need more assistance, feel free to ask.