What type of structure is the London Eye?

Here is the question :

WHAT TYPE OF STRUCTURE IS THE LONDON EYE?

Here is the option for the question :

Observation tower
Ferris wheel
Bronze statue
Residential building

The Answer:

And, the answer for the the question is :

Ferris wheel

Explanation:

[STC0016300]. The London Eye is the most popular paid tourist attraction in the United Kingdom, with over 3.5 million visitors coming through its doors each year. The capsules on the wheel each represent one of the city’s 32 boroughs, and it takes around half an hour for the wheel to make a full rotation. More than 5,000 individuals have gotten engaged on the Eye, and more than 500 weddings have taken place there since it first opened in 1999. It is also a popular attraction for families and groups of friends.