Correct answer - "Using pre-signed URL" : All objects by default are private. Only the object
owner has permission to access these objects. However, the object owner can optionally share
objects with others by creating a presigned URL, using their own security credentials, to grant
time-limited permission to download the objects. For more information visit
"Using bucket policy" - You can use this policy to limit users from a source IP address however
for time limitations you are better off with a pre-signed URL
"Using Routing Policy" - This concept applies to DNS in Route 53
"Not possible" - This is false, it is absolutely possible so read the documentation