comparison that vs those

[aflaamM589]

Hello Ron,
In following two sentences, is the second one incorrect, because those(plural) cannot stand for population(singular)?
NY city's population is greater than that of Montana,Wyoming, and Delaware all added together

NY city's population is greater than those of Montana,Wyoming, and Delaware all added together

thanks

[RonPurewal]

this is clearly not a random question, so, it needs to be asked on a thread along with the complete question that inspired it (in accordance with the forum rules -- in the correct folder, with the original source cited, with all original answer choices, and with the correct answer indicated).

this is important, because you can't just make up random examples with no context.
if there is not actually a single, larger, unified population that comprises x, y, and z, then it is ALWAYS nonsense to write "the population (singular) of x, y, and z", no matter what else might be happening in the sentence.