The question asks which Auto Loader schema evolution mode keeps the stream running while ignoring new columns.

Correct Answer: D — none

Why none is correct:

• In none mode, Auto Loader does not evolve the schema.
• Any new columns are ignored, and the stream does not fail.
• This is ideal when you want schema stability and don’t care about newly arriving fields.
• This mode is commonly used when you explicitly provide a schema, which matches many production scenarios.

Why the other options are wrong:

• A: dropNewColumns – Not a valid Auto Loader mode.
• B: addNewColumns – The default mode, but the stream fails first when new columns appear, even though they are added to the schema.
• C: ignoreNewColumns – Not a supported mode.
• E: failOnNewColumns – Immediately fails the stream and requires manual intervention.

Critical thinking tip:
If uninterrupted streaming is your priority and new fields are irrelevant to downstream consumers, none is the safest choice.