Encoding and written are the correct answers, respectively.
The communication process is made up of encoding and decoding processes. Encoding is the process used to turn thoughts into communication through a 'medium'. This medium can be either an e-mail, a phone call, a text message, or a face-to-face meeting. Thus, in this situation, we can say that Shelly engaged in the encoding process using a written medium, which was the e-mail she sent Susan.
