Your team is working on a new Internet of Things (IoT) application. The IoT devices need to prove their identity and establish encrypted communications channels between each other.
You want to create a private Certificate Authority (CA) so that you can create certificates with any subject name and expiration date you want.
How would you quickly implement this using the AWS Certificate Manager?

Answer options:

A.Use OpenSSL to generate a key for the private Certificate Authority. Create a certificate signing request and then self-sign the certificate. Import the new private CA to ACM.
B.Configure a private Certificate Authority (CA) using AWS Certificate Manager. Create a root CA to establish a new CA hierarchy.
C.Use OpenSSL to generate a private key for the new CA and import the key to ACM. In ACM, use AWS CLI create-certificate-authority to generate the private Certificate Authority.
D.In Amazon ACM, create a new private key and certificate signing request (CSR) for the private Certificate Authority. Generate new self-signed certificates for the private CA.

Answer: B
Option A is incorrect because you can directly create and manage a new private CA through ACM. OpenSSL is not required. Also, you cannot import a new private CA to ACM.
Option B is CORRECT because you can create a private CA using the ACM console. After filling in all the required information, such as CA subject name and key algorithm, you can fully manage the private CA.Option C is incorrect because you do not need to generate a private key for CA by yourself and import it to ACM.
Option D is incorrect because Amazon ACM helps to manage the internal process to create a private CA. No steps are required to create a private key or a CSR through ACM.
ACM Private Certificate Authority (CA) is a feature to create an entirely AWS-hosted private certificate authority (CA) for internal use. ACM can manage both the root CA certificate and any subordinate CA certificates. Details can be found in
Reference:
https://docs.aws.amazon.com/acm-pca/latest/userguide/PcaWelcome.html