dell precision 380/ win 7 / 3 hard drives all needed to boot

I am trying to get my computer to boot up using only one hard drive. Currently it will only boot up
if all 3 drives are connected. I am sending a screenshot of the disk management screen so
someone with know how can diagnose why all 3 are interconnected and need each other.
I bought a stand alone drive copier to copy my hard drive to a larger drive. I would like to make the copy of the "C" drive on the 250 gb. drive shown but I think if I change something on that drive the comp. will not boot at all.
I hope that i conveyed this so that people can understand because it is somewhat confusing. My computer skill level is decent but i need assistance on this.
I would add a second drive once I clear this up.

Thanks,

Joe

That makes so much sense. If I proceed and it does not rectify the problem will I be able
to switch back, not being able to boot?
Keep in mind that I think your solution sounds right and I have confidence in your answer, I want to have a plan just in case.

Thanks,

I just meant that if it does not work i need to have use of my computer. I agree that once I figure this
out I would not go back to this configuration.
In the past when i tried to deal with this, the 100 mb partition caused problems. I think that is why
it need the "R" drive to boot. It seems that it should be on the "C" to avoid any conflicts.

sorry, you are correct. This 100 mb partition is necessary to boot the computer.
Why is it not on the "C" drive?
No dual boot on this box.
I may have installed another OS years ago on another disk but
I honestly don't remember. I am just trying to correct the mess.
How do I check the bios order?

C is booting itself as signified by the System Active flags on it, while the Boot flag confirms it is the OS partition currently booted. Unplug all drives except C to confirm it will boot itself.

You can then plug back in Disk 2 to clone Disk 0 to it using your cloning or imaging program. I recommend the free premium Acronis app that comes with any Seagate or Western Digital drive in the mix. The Manual is easy to understand and on the Download page: Seagate Acronis cloning free util / WD Acronis free cloning app. Many here like free Macrium - Image your system.

Use the Acronis Automatic setting for size adjustment, or if your cloning app doesn't have this then clone it as is and later Extend C in Disk Mgmt if you want. Partition or Volume - Extend

Be sure if prompted to include Active flag, MBR and Track0 so clone/image will boot. If it fails to boot, confirm the Partition is Marked Active, power down to unplug the source HD, then run Startup Repair - Run 3 Separate Times until it boots.

Before reusing Disk1 I would wipe it with Diskpart Clean Command to remove old boot code. This is the cleanest way to delete an OS - which should at least be deleted in Disk Mgmt along with its SysReserved partition, if not wiped.