Cannot ping AWS EC2 instance with public IP

I cannot ping my EC2 instance with which has a public IP associated with it. Before posting here, I read Cannot ping AWS EC2 instance. It didn't help:

Here's how I have things set up:

I created a new Amazon Linux t2.micro instance using all the defaults.

After creation, it didn't have an IPv4 Public IP in the EC2 | INSTANCES | Instances.

So I went to EC2 | NETWORK & SECURITY | Elastic IPs, and clicked the Allocate Elastic IP address button. After the Public IPv4 address column showed an address, I clicked Actions | Associate Elastic IP address.

I went back to EC2 | INSTANCES | Instances, and the IPv4 Public IP column shows the address I just created.

Still cannot ping.

So I went to EC2 | NETWORK & SECURITY | Security Groups, clicked the link for the security group associated with the instance and added an inbound and outbound rule like so:

All traffic          All        All       0.0.0.0/0 
All ICMP - IPv4      ICMP       All       0.0.0.0/0

Still cannot ping.

So I went to VPC | Internet Gateways, clicked the Create internet gateway button, selected the defaults, and then attached the internet gateway to the VPC which is associated with the instance.

Still cannot ping.

So I went to VPC | SECURITY | Network ACLs, Edit Inbound and Edit Outbound rules. This is what I have for both:

Rule #   Type              Protocol       Port Range      Source       Allow / Deny
100      ALL Traffic       ALL            ALL             0.0.0.0/0    ALLOW
101      All ICMP - IPv4   ICMP (1)       ALL             0.0.0.0/0    ALLOW

Still cannot ping.

What else is missing to be able to ping? Yes, I can ping other hosts on my network... just not to AWS and the public IP address listed for that EC2 instance.