Which of the following can be used to control how far your routes get advertised when using AWS Direct Connect and a public VIF?

Answer options:

A.Use BGP communities.
B.Use BGP headers.
C.Use AS_PATH prepending.
D.Use MED.

Answer – A
This is also mentioned in the AWS Documentation.
BGP Communities
AWS Direct Connect supports a range of BGP community tags to help control the scope (regional or global) and route preference of traffic.
Scope BGP Communities
You can apply BGP community tags on the public prefixes you advertise to Amazon to indicate how far to propagate your prefixes in the Amazon network—for the local AWS Region only, all regions within a continent, or all public regions.
You can use the following BGP communities for your prefixes.
7224:9100—Local AWS Region
7224:9200—All AWS regions for a continent (for example, North America–wide)
7224:9300—Global (all public AWS Regions)
All other options are invalid since you need to use BGP communities.
For more information on routing and BGP communities, one can visit the below URL
https://docs.aws.amazon.com/directconnect/latest/UserGuide/routing-and-bgp.html