Verbal Ability - Sentence Correction - Discussion

Answer can't be "A" as we use greater to compare not greatest. Option "B" and "D" compare population of tokyo with other towns so they get rejected. Although option "C" compare population with population but in comparison we take two thing at a time and in option "C" it compare population of tokyo with a group of town's population.

Now here we are comparing population (main focus) not the town.

If population is focused than the marked answer is correct. Also, Population is uncountable noun and singular use so no use of 'Those'.

The population of Tokyo is greater than that of any other town in the world. (correct).

The other way could be:

The population of Tokyo is greatest among all other town in the world. (but that again is not any of the option).

Now lets have bottom up approach.

Option A- superlative degree used and any other refers to individual city. Greatest among any other (incorrect) greatest among all other (correct).

Option B - you can deduce from above point that it's incorrect.

Option C& D- see the first & second paragraph.

But the answer should be A Because it is comparing all the towns of the world and for comparing more than two things superlative degree should be used.

And while seeking all the towns over the world greatest word should be used.

This answer sounds ambiguous. I guess greater than any other town would in the world complete the sentence.