What command line redirection characters instruct the shell to read from the current input source until a specific word, on a separate line and without leading and trailing characters, is reached?

What command line redirection characters instruct the shell to read from the current input source until a specific word, on a separate line and without leading and trailing characters, is reached?

A.
<<

B.
<l

C.
!<

D.
$<

Explanation:
Example:
$ echo <<foobar
Hello
foobar
Hello