Will the boot drive always be assigned "C"?

[denzilwright31]

I have an Acer ES1-132-C974. It has a soldered 32GB eMMC as default. As we all know, when the system takes it's portion, practically nothing is left for the user. I've installed an SSD with a clone of the eMMC. However, the laptop still reads the eMMC as "C:". I want the SSD to be read as "C:" permanently and the eMMC to be reassigned to "D:". That way, all my system files and logs and so forth will automatically be written and read on the SSD while the eMMC is kept as a secondary storage medium like an external hdd or SD card. What I'm practically saying is that the computer does it's normal task as if the SSD was the only drive presently installed.

I'm asking if changing the boot order, by setting the SSD first priority, will automatically always assign the SSD as "C:" and not just boot from the SSD and then keep the eMMC as "C:" instead of reassigning it to "D:" since it was not booted from. (Is the booted drive always "C:"?)

When answering please use an example like, "If you set a USB as first priority and it has the boot files, it will be read as 'C:' " or "once any storage medium with a boot file is set as first priority in boot order, it will always be assigned 'C:' when the computer loads up". Just try to make it as clear as possible. Please, I'm begging you

 

[CountMike]

Windows and most other OSs always reserve letter C: for drive/ partition they boot of.
Example:
2 disks in a computer.
One disk with windows 10 installed on it.
Another one with windows 7 installed on it.
BOOT with first disk and it will be C: and other one D: (or some other letter).
BOOT with second disk and letters will be reversed, On W7 it wll be on C: and disk with W10 will be D: (or some other letter.
Letters are assigned to a disk by OS and in some other situation they may be different but one that was BOOTed of will always be C:

Same goes for partitions if on same disk.

 

[denzilwright31]

Windows and most other OSs always reserve letter C: for drive/ partition they boot of.
Example:
2 disks in a computer.
One disk with windows 10 installed on it.
Another one with windows 7 installed on it.
BOOT with first disk and it will be C: and other one D: (or some other letter).
BOOT with second disk and letters will be reversed, On W7 it wll be on C: and disk with W10 will be D: (or some other letter.
Letters are assigned to a disk by OS and in some other situation they may be different but one that was BOOTed of will always be C:

Same goes for partitions if on same disk.

Thanks @CountMike