在一个HTTP标头中发送多个cookie

i am confused about how cookies work in general.

Suppose i have

  • Cookie A for www.mysite.com (let's call it Path A)

  • Cookie B for www.mysite.com/dir1 (Path B)

  • Cookie C for www.mysite.com/dir1/dir2 (Path C)

Now if I visit root path, only Cookie A is sent to server and used? If i request files in Path B, Cookie A and B are both sent to server, but only B is used? If i tey to access files in Path C, all 3 cookies are sent, only C is used?

If it indeed works that way, what happens to the unused cookies?

Could the situation where multiple cookies with the same name exist for ONE particular webpage exist? Thanks