Fill in the blanks with the most appropriate option:-

This building is _________ among all the buildings in the city.

the oldest

The most appropriate option to fill in the blanks is the oldest.

The sentence "This building is the oldest among all the buildings in the city" means that this building is older than all the other buildings in the city. The other options are not as appropriate.

• Elder is an adjective that means older than another person or thing. This does not make sense in the context of the sentence, as the building is not older than a person or another building.
• Old is an adjective that means having existed for a long time. This is a less specific word than "the oldest", and it is not the most appropriate word to use in the sentence.
• Older is the comparative form of the adjective "old". This does not make sense in the context of the sentence, as the building is not simply older than the other buildings, but it is the oldest building in the city.