What do the brackets in the following quote indicate?
Dillard was "stunned into stillness as [the weasel] was emerging from beneath an enormous shaggy wild rose bush four feet away."

A.
There was a word missing in the original text.

B.
The author, Annie Dillard, wanted to emphasize the words within the brackets.

C.
The writer of this sentence made changes to the original text.

D.
Parentheses are overrated.