When planning a memory upgrade, you discover that Windows 8 reports 4 GB of memory installed. In BIOS/UEFI, you see that two of four slots are populated. You install two 2-GB DIMMs in the two empty DIMM slots. When you boot the system, Windows 8 still reports 4 GB of memory. Order the four steps you should take to troubleshoot the problem of missing memory. a. Open the case and verify that the DIMM modules are securely seated. b. Go into BIOS/UEFI and verify that it recognized 8 GB of installed memory. c. Open the System Information window to verify the edition or version of Windows 8 installed. d. Inspect the DIMMs you installed to verify that they match the existing DIMMs and those the motherboard can support

The memory upgrading means increases the memory in the computer system as in the given question when the user has planned to memory upgrading the user has seeing that the two out of the four slots are crowded. In the two empty DIMM holes, you mount two 2-GB DIMM when the user restarted the computer system they faces same problem they will solve there problem by the following steps.

Activate the operating system of the window to check for the installed Windows 8 edition or the variant.
Go over to the BIOS / UEFI and confirm that 8 GB of activated memory has been accepted.
Activate the case and make sure the DIMM components are sitting safely.
Monitor the DIMMs the user have installed to validate that they match original DIMMs and can support the motherboard.

Therefore Option(c)--->Option(b)--->Option(a)---->Option(d) is the correct order.