The correct answer is 3. Talk, line, persuasion
Step-by-step explanation:
The purpose of a thesaurus is to provide synonyms to a word; however, in some cases, a word might have two or more meanings, and therefore, the thesaurus will provide synonyms with different meanings. This occurs in the case of the word pitch means field, talk, launch, or even raise.
In the case of the sentence "The salesman gave his pitch, but it wasn't convincing enough to make the customer buy the vacuum cleaner" the word "pitch" is used to refer to the speech said by the salesman to try to convince the customer, in this context, the meaning of the word "pitch" matches with the synonyms "Talk, line, persuasion."