Which resource is most relevant when looking for synonyms, antonyms, and closely related words?

unabridged dictionary

etymology dictionary

thesaurus

slang dictionary

Question

Which resource is most relevant when looking for synonyms, antonyms, and closely related words?

unabridged dictionary

etymology dictionary

thesaurus

slang dictionary

anonymous · Answer

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anonymous · Answer

It's ironic because my name is also Fabian.

Although that fabian is an idiot. It's definitely not an Etymology Dictionary. 
That the study of words Origins, how they came to be what we call them now. 

                                           The Answer is (C)!! 
the·sau·rus
THəˈsôrəs/Submit
noun
a book that lists words in groups of synonyms and related concepts.