Explanation/Reference:
Explanation:
Shortcut trusts are one-way or two-way, transitive trusts that can be used when administrators need to optimize the authentication process. Authentication requests must first travel a trust path between domain trees, and in a complex forest this can take time, which can be reduced with shortcut trusts.

Incorrect Answers:
B: Use external trusts to provide access to resources located on a Windows NT 4.0 domain or a domain located in a separate forest that is not joined by a forest trust.
C: Filters users or SIDs from one domain
D: Use external trusts to provide access to resources located on a Windows NT 4.0 domain or a domain located in a separate forest that is not joined by a forest trust References:
https://technet.microsoft.com/en-us/library/cc737939(v=ws.10).aspx
https://technet.microsoft.com/en-us/library/cc775736(v=ws.10).aspx
https://technet.microsoft.com/en-us/library/cc772633(v=ws.10).aspx