The reactions that can be used to prepare benzylamine are (a) Reduction of benzamide with \(\mathrm{H}_{2} / \mathrm{Pd}\). (b) Reduction of benzenecarbonitrile with \(\mathrm{SnCl}_{2} / \mathrm{HCl}\). (c) Reaction of potassium phthalimide with benzylbromide followed by hydrolysis. (d) reaction of benzoyl chloride with ammonia.

First, we should understand what products each of the reactions form. Given reactions are: (a) Benzamide (C6H5CONH2) reduced by \(\mathrm{H}_{2} / \mathrm{Pd}\). (b) Benzenecarbonitrile (C6H5CN) reduced by \(\mathrm{SnCl}_{2} / \mathrm{HCl}\). (c) Reaction of potassium phthalimide (C8H4KNO2) with benzylbromide (C6H5CH2Br) followed by hydrolysis. (d) Reaction of benzoyl chloride (C6H5COCl) with ammonia (NH3).

It is essential to understand the reaction mechanism for each reaction to know which one will lead to benzylamine: (a) Benzamide (C6H5CONH2) when reduced by \(\mathrm{H}_{2} / \mathrm{Pd}\), will form benzylamine (C6H5CH2NH2) as the product. (b) Benzenecarbonitrile (C6H5CN) when reduced by \(\mathrm{SnCl}_{2} / \mathrm{HCl}\), will form \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{NH}_{3} \mathrm{Cl}\) (benzylamine hydrochloride) as the product, which can produce benzylamine by treatment with a base. (c) Reaction of potassium phthalimide (C8H4KNO2) with benzylbromide (C6H5CH2Br) followed by hydrolysis will form benzylamine (C6H5CH2NH2) and phthalic acid. (d) Reaction of benzoyl chloride (C6H5COCl) with ammonia (NH3) will form benzamide (C6H5CONH2) and hydrochloride.

Since the goal is to prepare benzylamine, we will consider only those reactions that form benzylamine C6H5CH2NH2. Based on the product formation: (a) Reduction of benzamide with \(\mathrm{H}_{2} / \mathrm{Pd}\) directly forms benzylamine (C6H5CH2NH2). (b) Reduction of benzenecarbonitrile with \(\mathrm{SnCl}_{2} / \mathrm{HCl}\) forms benzylamine hydrochloride. However, benzylamine can be produced by treatment with a base. (c) Reaction of potassium phthalimide with benzylbromide followed by hydrolysis forms benzylamine (C6H5CH2NH2). (d) The reaction of benzoyl chloride with ammonia doesn't lead directly to benzylamine.

The reactions that can be used to prepare benzylamine are: (a) Reduction of benzamide with \(\mathrm{H}_{2} / \mathrm{Pd}\). (b) Reduction of benzenecarbonitrile with \(\mathrm{SnCl}_{2} / \mathrm{HCl}\), followed by treatment with a base. (c) Reaction of potassium phthalimide with benzylbromide followed by hydrolysis.