When investigating a computer forensics case involving the use of Blackberry devices and Microsoft Exchange Server, an investigator may need to search the RIM (Research in Motion) Messaging center to find emails sent from a Blackberry device. The RIM Messaging center is a centralized system that manages email and other messaging traffic for Blackberry devices. When a user sends an email from a Blackberry device, the email is routed through the RIM Messaging center to the recipient's email server. In some cases, Blackberry Enterprise Server may be used to manage Blackberry devices and their connectivity to the email system. In such cases, an investigator may also need to examine the Blackberry Enterprise Server to collect evidence related to email traffic and other messaging activity. However, to find emails specifically sent from a Blackberry device, the RIM Messaging center is the most likely place to look.

The correct answer is C. Microsoft Exchange server. When a Blackberry device sends an email, the email is sent to the Blackberry Enterprise Server (BES), which then forwards the email to the Microsoft Exchange Server. The email is then stored on the Exchange Server, where it can be accessed and searched by the investigator. Here's a brief overview of the other options: A. RIM Messaging center: This is not a component of the Blackberry Enterprise Server or Microsoft Exchange Server. B. Blackberry Enterprise server: While the BES does handle email sent from Blackberry devices, the email is not stored there; it is forwarded to the Exchange Server. D. Blackberry desktop redirector: This is a software component that allows Blackberry devices to synchronize with a user's desktop computer, but it is not involved in the email sending process.