Final answer:
Instant Messaging in Business is faster than e-mail for brief business messages but can be more complex; emails often provide better security and privacy options in a professional setting.
Step-by-step explanation:
Among the options provided about the use of computer-based IM (Instant Messaging) for brief business messages, the statement that is true is "IM is faster than e-mail, though more complicated to use." Instant Messaging enables real-time communication, making it swifter for brief exchanges compared to e-mail.
However, it can be more complex in terms of managing a continuous conversation and may require familiarity with more instantaneous communication norms and user interfaces.
E-mail, on the other hand, may encounter unwanted messages but typically has more robust security and privacy protocols in a business context. It is important to remember that business e-mails should be professional and consider the potential audience beyond the direct recipient.