I think its b because it's like *somebody is talking right the speaker is.

Read the corporate document. upon becoming customers of topguide financial group, all clients agree to the following: information provided by employees of topguide financial group is subject to change without notice. any opinions therein are solely those of the author and may not reflect the views of topguide. topguide reserves the right to monitor, retain, and disclose all electronic communications, including email, that pass through its servers and communication systems. which text feature, if added, would best aid the reader’s understanding of this passage? a caption that lists the source of the text a heading that indicates the text’s purpose a graphic that illustrates the information in the text a recipient line that shows the text’s audience