AWS Certified Security - Specialty (#34)

While securing the connection between a company's VPC and its on-premises data center, a Security Engineer sent a ping command from an on-premises host (IP address 203.0.113.12) to an Amazon EC2 instance (IP address 172.31.16.139). The ping command did not return a response. The flow log in the VPC showed the following: 2 123456789010 eni-1235b8ca 203.0.113.12 172.31.16.139 0 0 1 4 336 1432917027 1432917142 ACCEPT OK 2 123456789010 eni-1235b8ca 172.31.16.139 203.0.113.12 0 0 1 4 336 1432917094 1432917142 REJECT OK What action should be performed to allow the ping to work?

In the security group of the EC2 instance, allow inbound ICMP traffic.
In the security group of the EC2 instance, allow outbound ICMP traffic.
In the VPC's NACL, allow inbound ICMP traffic.
In the VPC's NACL, allow outbound ICMP traffic.