What is the best reagent to convert nitrile to primary amine?

When acetamide reacts with $Br_2$ and caustic soda,then we get

Gabriel phthalimide synthesis is an example of

Explain the reaction of diazotization with suitable examples.

Nitrobenzene combines with hydrogen in the presence of platinum to produce

In an acidic medium,nitrobenzene is reduced to aniline as shown in the following reaction: $C_6H_5-NO_2 + 6[H] \rightarrow C_6H_5-NH_2 + 2H_2O$. Which of the following is used as the reducing agent in this reaction?