So,

One of the tricks was to see the difference between

When you create a clustered or nonclustered index, the IGNORE_DUP_KEY option must be set to ON (the default setting).

AND

When you create a clustered or nonclustered index, the IGNORE_DUP_KEY option must be set to OFF (the default setting).

At first sight I saw IGNORE_DUP_KEY and the default setting and my thought was: that is correct.

So we have to check every word I guess 🙂

Leo