The correct option is
A Tokyo - Proper Noun; city, world - Common Nouns
Common nouns include both abstract as well as concrete nouns. These
nouns name things, whether abstract or concrete. By abstract we mean,
something that can be sensed or felt, and not touched. They include
emotions and states of being. Concrete nouns can be seen, felt, tasted,
smelled and heard.
Proper nouns name a specific person, place or animal, for e.g. Amy, America.
Option A: In the given sentence, 'Tokyo' is the name of a particular city, hence it's a proper noun.
The
nouns 'city' and 'world' are both common because they're general names. ('Tokyo' makes a common noun like 'city' more specific.)
Hence option A is correct.
Options B, C and D: 'Tokyo' cannot be a common noun as it names a specific city.
'City' and 'world' cannot be proper nouns because they're general names.
Hence these options are incorrect.