What communication channel would be most appropriate when a written record or formality is required?

B). Letter.

Explanation:

A variety of communication channels are employed as the manner in which a message is transferred or delivered from one individual to another individual or group.

As per the question, in order to convey a written and formal record to a person or authority, 'letters must be used' as they contain specific information in a precise, sophisticated, and notable form. The other channels are employed for distinct purposes like 'reports intend to present data' while 'e-mails help in providing reaction or feedback' instantly and 'blogs proffer the digital particulars to the readers'. Therefore, option B is the correct answer.

The correct answer is D, between sentence five and six

Explanation:

The best place to add an example of how her sister is like a friend is between the sentences five and six, because it is there where she is talking about her sister´s characteristics as a friend and those things that make her a good friend, she could continue with the description of her characteristics between these two sentences.