Short answer, I bet it's that first one you posted. GM part number 07848635.
Long answer with more explanation...
This diagram for a '97-'98 C1500 Suburban with a one piece driveshaft from Nemiga Chevrolet shows two part numbers for slip yokes.
https://nemigaparts.com/cat_spares/epc/chevrolet/54c-c/05/tx05-107/
One of them is that 07848635 you posted, and it has notations of "C1(16)" and "w/out balancer". The other is 88963576 which has a "K1(16)" notation and is mentioned as the fix for a '99 AutoTrac 4WD Yukon with the driveline "clunk" issue in this thread:
https://www.gmt400.com/threads/heres-your-fix-for-the-tahoe-yukon-driveline-clunk.30421/
My best guess, without measuring anything or actually investigating the parts any further... The 07848635 part with the "C1" notation is probably for "C" designated 2WD trucks, and the 88963576 part mentioned in the driveline clunk thread is probably for the "K" 4WDs.