What is Amazon S3 ?

It's an internet object storage service provided by amazon.

Object storage differs from filesystem storage and block storages, that each object typically includes the data itself, a variable amount of metadata, and a globally unique identifier.

S3 stands for Simple Storage Service and is a part of the Amazon Web Services (AWS). It is an online storage facility on Amazon's cloud platform. Amazon uses the concept of buckets which are like containers to store data on their public cloud offering. As part of your AWS subscription, you could enable S3 service which opens up a bucket for you which you can further use to store any type of data.

It's a web storage or in simple terms internet based storage.

There are two types of storage available in the market.

1. BLOB Storage - used for file system
2. Object Level Storage - Used to store objects like Photos, Media file, Videos, Songs, .. any type of object. 

Amazon S3 is an Object  level storage. It can be accessed over the internet. We can use Rest API calls to access this storage. It is one of the most cost effective solution available in the market. 

its more of An Internet Storage

Amazon S3 (Amazon Simple Storage Service

c. An Internet Storage

Amazon S3 (Simple Storage Service) is an online file storage web service offered by Amazon Web Services.

AMOAZON S3 is ( Amazon Simple Storage Service),  provides secure storage area through web services interfaces, that  developer’s and IT teams  can used .

that mean it contain allsecurity and storge and web  so all the above is surable answer

c. An Internet Storage

c. An Internet Storage

Amazon Simple Storage Service is cloud disk from Amazon. This we can use backup file system.