I can't understand the whole thing that he said.

Question

(What is the meaning of the sentence?
1. I can't understand what he said at all.
2. I can't understand some(?) of what he said.
3. I cann understand almost all the things that he said, but not all.)

Answer 1

#3 comes the closest to the original sentence. #2 is close, but #3 states the idea better.