Explanation:

Why C is Correct

On a Configuration Attribute, there’s a checkbox called:
Apply to Product Options

When set to TRUE:

The attribute value is copied down to all related Product Options in the bundle.
This means option-level Quote Lines also see the attribute’s value.
That’s crucial if your Price Rule uses that value to drive discounts or price changes on the options.

If you don’t check “Apply to Product Options”:

The attribute value stays only on the parent bundle product’s quote line.
The price rule would not see that value on the options, so the discount wouldn’t apply there.

Hence, C is the correct answer.

Why Other Options Are Incorrect

A. Ensure that Apply Immediately has been set to TRUE.

✘ Incorrect.
“Apply Immediately” triggers a refresh in the configurator when you change the attribute value.
It does not control whether the value applies to product options.

B. Ensure that the Default Object field is set to Quote Line.

✘ Incorrect.
The Configuration Attribute generally writes to fields on either:
Product Option → if Apply to Product Options is FALSE
Quote Line → if Apply to Product Options is TRUE or if synced fields exist

However, simply changing the Default Object to Quote Line doesn’t ensure propagation to options.

D. Ensure that the Configuration Attribute’s Feature field is set to Null.

✘ Incorrect.
That field merely determines whether the attribute belongs to a specific Feature in the configurator UI.
It has no impact on applying values to product options.