OK!
So, as I suspected, C and D are two individual drives.
Whoever built your PC with a 30GB drive (with 8GB taken up by a Recovery partition!) should be taken out back and shot. Unless of course this is a spouse who did it. Any other relative/friend/PC store....they need to never configure a PC again.
That is simply far too small for a current Windows OS drive.
And no, you can't expand the C partition into the D space, because they are two individual drives.
My suggestion?
Actually, this involves multiple steps.
1. Undo the BitLocker encryption. Unless you really need it, and know what you are doing with it, and how to recover...that is actually quite dangerous and may lead to total data loss
2. Find whatever data is on the D drive, and save that elsewhere. It looks to be very minimal, so an SD card should do it
3. Migrate the current Disk 0 to the Disk 1. Your Disk 1 (465GB) will become the C drive.
4. Disconnect the existing 30GB drive, and put it in a drawer somewhere.
For #3 - Acronis Trueimage, Easus Todo, Macrium Reflect, Casper...they can all do that migration pretty easily.