What are three implications of the planned change?

A customer uses Azure Cognitive Search.

The customer plans to enable a server-side encryption and use customer-managed keys (CMK) stored in Azure.

What are three implications of the planned change? Each correct answer presents a complete solution. NOTE: Each correct selection is worth one point.
A . The index size will increase.
B. Query times will increase.
C. A self-signed X.509 certificate is required.
D. The index size will decrease.
E. Query times will decrease.
F. Azure Key Vault is required.

Answer: A,B,F

Explanation:

"Customer-managed keys require an additional billable service, Azure Key Vault, which can be in a different region, but under the same subscription, as Azure Cognitive Search. Enabling CMK encryption will increase index size and degrade query performance."

same document also lists Azure Key Vault as a requirement:

https://docs.microsoft.com/en-us/azure/search/search-security-overview#data-protection