For First one,
In option A, The nucleophilic centre that will preferably attack is S- after resonance.
In Option b, the configuration doesn't change cuz its the nucleophile.
Option C, NaI is more soluble in acetone than NaBr, hence the reaction won't go in the forward direction to a great extent.
In Option D, The lone pair on oxygen attacks the Sulphur in SOCl2, a molecule of HCl is removed which is neutralised by pyridine. On Adding Cl- Sn2 can now take place due to bulky leaving group.