The `<ltng:require>` tag in Lightning Components has several capabilities related to loading external JavaScript libraries. Here are the relevant options from your list:
1. **Loading files from Documents** - This is not a capability of `<ltng:require>`. It primarily loads scripts from URLs.
2. **Loading scripts in parallel** - This is correct. The `<ltng:require>` tag allows scripts to be loaded in parallel, which can improve performance.
3.