Everything is good with option 3 except that it says only humans have the ability to think, something that is nowhere to found in the passage. 3 can be ruled out. Option 1 goes out because displaced reference is a distinguishing feature of language, not of humans. Option 1 can be ruled out. Option 4 goes out because the passage says that thought precedes all meaningful communication, while option 4 says that thought precedes all speech acts, something that may not always be the case. Thus option 4 too goes out. Option 2 is succinct and does not have any distortions or misrepresentations.