I am in trouble with my computer.
I installed Windows10 at first.
I then installed Ubuntu 18 and the grub occurred every time I boot my computer.
Later, I installed Ubuntu 16. The grub of Ubuntu 16 seemed to replace the grub of Ubuntu 18.
Now, I want to delete the Ubuntu 16, but I want to keep the Ubuntu 18.
Should I delete the "/boot" partition? Should I keep the "/boot/efi" or "/boot/grub" partition?
And what is the recommended size for "/boot" and "/boot/efi" in Ubuntu 20 if I try installing it later? Will the Ubuntu 20 move the kernels from Ubuntu 18 to Ubuntu 20?
Thank you very much.