Lassaigne's test for nitrogen is negative for which compound?

In the Lassaigne's test for nitrogen in an organic compound, he prussian blue colours is obtained due to the formation of:

During Lassaigne's test, nitrogen present in the organic compound is converted into

Sometimes, the colour observed in Lassaigne's test for nitrogen is green. It is because

What will happen during lassaigne's test for nitrogen if the compound also contains sulphur?

For which of the following ,the Lassaigne's test for nitrogen will not be positve ?