Which part of the communication process requires skill, attitudes, knowledge, and the social-cultural system?

The part of the communication process that requires skill, attitudes, knowledge, and the social-cultural system is: Encoding
Encoding is a process to produce a message that could be understood by the audience. Since each ethnics/and cultures may perceive a same message in a different manners, we need to have all the knowledge about the skill, attitudes, knowledge, and the social-cultural system

It's most likely choice a, it makes the most sense in my opinion.