In The Call of the Wild, what exploit did Buck accomplish that made John Thornton jubilant?

Buck attacked "Black" Burton for punching John Thornton.

Buck won a bet for John Thornton.

Buck was willing to jump off a cliff for John Thornton.

Buck attacked "Black" Burton for punching John Thornton.

Buck attacked "Black" Burton for punching John Thornton.

In The Call of the Wild, Buck accomplished an exploit that made John Thornton jubilant by attacking "Black" Burton for punching him.

To find this answer, you can read the book and refer to the specific chapter or part where this incident occurs. If you have a physical copy of the book, you can look for keywords like "exploit," "Buck," "John Thornton," and "Black Burton" using the index or table of contents. Once you locate the relevant section, you can read the passage to understand the details of the exploit that occurred. If you have an electronic version of the book, you can use the search function to look for these keywords to find the specific chapter or part.