Option D Amazon Machine Image (AMI), fits here. AMIs are built to be deployable templates for EC2-OS, apps, security settings all packaged so you can spin up identical instances. The other options are either storage or infrastructure as code, not actual templates for launching EC2s. Pretty sure D is the way to go but let me know if I'm missing something.
I was thinking B here since CloudFormation lets you template AWS resources, including EC2 setup. It's a bit confusing, though, because it's not the image itself but you can package all requirements into the stack. Anyone else see it that way?
I'd probably go with C here since Amazon Forecast is specifically made for ML forecasting tasks. It's focused but still involves building and deploying models for time series data. Not 100 percent sure since D covers broader ML workflows, so happy to hear other takes.