To make a Lightning Web Component (LWC) available in Salesforce Classic, you can embed it in a Visualforce page using Lightning Out.
Option D: Use the Lightning Out JavaScript library to embed the Lightning Web Component in a Visualforce page and add to the page layout.
Lightning Out allows LWCs to be embedded in Visualforce pages.
The Visualforce page can then be included in Salesforce Classic interfaces.
Why Not Other Options:
Option A: Visualforce components cannot directly contain LWCs.
Option B: Wrapping an LWC in an Aura component and surfacing it as a Visualforce tab doesn't make it available on page layouts.
Option C: You cannot invoke an LWC from a Visualforce page using an Apex method call.
Reference:
Lightning Out for Visualforce:
"Lightning Out is a feature that extends Lightning components to any web page. Use it to embed Lightning web components in a Visualforce page."
- Lightning Web Components Dev Guide: Use Lightning Web Components in Visualforce Pages