**CORRECT ANSWER:**

* **C. Standard controller save()** (The `apex:page` standardController attribute takes precedence over any extension methods with the same name.)

**INCORRECT OPTIONS:**

* **A. This is not correct as there won't be a runtime error.** Visualforce will attempt to call a matching method based on the context.
* **B. This is also not correct as the standard controller has higher priority for the `save` action when both are present.**
* **D. Similar to B, ExtensionB's save method won't be called because the standard controller has priority.**

**Explanation:**

In Visualforce pages with a `standardController` attribute, the standard controller's methods are used by default for actions like `save`. Even though you have extensions `ExtensionA` and `ExtensionB` with their `save` methods, the standard controller's `save` method will be triggered when the button is clicked.

If you want to use a custom `save` logic from your extensions, you'll need to:

1. Rename the methods in your extensions (e.g., `customSave` instead of `save`).
2. Call the extension method from the standard controller's `save` method using `ExtensionName.customSave()`....

Answer is B

The Answer is B. ExtensionA save().

Overrides are defined by whichever methods are defined in the “leftmost” extension, or, the extension that is first in the comma-separated list. Thus, the save method of ExtensionA is overriding the method of ExtensionB.

Answer is B
Refer: https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_controller_extension.htm

It's: B. ExtensionA save(). What serj said.

I think it's A. The leftmost extension override the standard controller and has priority