Here's the response from the factory:
The MC0152 BIOS queries the processor capabilities registers to see whether it provides support for the VT-d feature. If the processor includes support, the enable/disable question will be presented by the user. If the processor does not contain support, however, no question will be presented.
Bottom line, whether you will see the question is dependent upon whether or not your processor actually provides support for the VT-d feature...
Thank you for the reply.
I am using an Intel Core i7-4770 Processor (8M Cache, upto 3.90 GHz). This processor supports Intel Virtualization Technology for Directed I/O (VT-d) according to http://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz