Which of the following online communication tools would be the most effective way to communicate confidentially and directly with each of your vendors$$ sales managers, as necessary, while you are traveling around the country making sales calls?

$$

a$.$ Sending and receiving email using an email client installed on your home computer c$.$ Sending and receiving web$-$based email using a laptop computer

b$.$ Subscribing to a newsgroup that focuses on automotive topics d$.$ Posting messages to a social networking site