Answer:
C. email
Explanation:
The Email should be termed as electronic mail which is to be used to convey a message in an instant seconds
It is to be expressed in a formal way of communicating any message, notice, The important thing, etc
It is a quick, easy to use and most convenient way to send a message
Here in the given situation, since John wants to convey the best wishes for a meeting that scheduled later so here the email is the best and appropriate way to communicated as it is business documented also
