It would actually be 2-A (or even Low 1-C, which I will get to why soon), as the characters used for "countless worlds" is "不可胜数的世界"
Or in English:
"The untamed imaginary energy surges endlessly through space-time vasculature, and forms at its tips "galaxies" that humans can understand — in other words,
countless worlds."
As for why this may be Low 1-C...well.
"不可数" is what is use to describe how large "uncountable" is in an uncountable set. Hell, even the word for "uncountable set" is "不可数集".
Now you may ask "what about the "胜""? Well, that's a bit tricky to explain. But it may mean "able to do" in this context.
So: "不可胜" may mean "unable to do", as 不可 means "cannot".
数 means "to count/to number"
So in all, 不可胜数 may mean "unable to count/number"; uncountable.
Which again, 不可数 is what is used to describe the "uncountability" of an uncountable set. So, 不可胜数的世界 may mean "uncountable worlds".
Now it cannot be "countless" in a finite sense, as the word for that is "无数“, which is basically used for a large amount of something which is too much, although still finite, to count. Nor can it be just be simply infinite...as that is 无限.
In fact, "countably infinite" in Chinese is "可数无限", and "
uncountably infinite" is "
不可数无限"
So again, "不可数" explicitly refers to the uncountability of an uncountable set.