Which of the following option(s) is/are true?

If the compound contains N, S and Halogen they get converted into soluble sodium salts in the preparation of sodium fusion extract.    

The presence of the Chlorine in the Compound can not be confirmed with Lassaigne’s Test

When ${\left(C{H}_{3}COO\right)}_{4}Pb$ solution is added to the acidified Lassaigne’s extract of an organic compound containing S, a black precipitate of PbS is formed

To the sodium extract, cold.dil. ${\text{HNO}}_3$  should be added before treating with  ${\text{AgNO}}_3$ to detect the halogen if the compound has $N$ or $S$.