If I'm not missing something screechingly obvious, you do it in BIOS.
Disconnect the present 'C'
Enter BIOS - hit <DEL> or summat whilst booting,
Navigate to Advanced Options
Make your present 'T' the first drive... since it's cloned C you should have an identical content?
Hit F10, confirm,
Sit back & see if it works.
Obviously the DEL, F10 is on my machine; yours may or may not use different command keys.