The correct answer is option 3, Zinc (Zn). When a metal displaces hydrogen from an acid, it forms a salt. This process is known as a displacement reaction.

Let`s explore the other options to better understand why they are not the correct choices:

Option 1: Sulphur (S) is a non-metal and does not have the ability to displace hydrogen from acids.

Option 2: Silicon (Si) is also a non-metal and does not have the ability to displace hydrogen from acids.

Option 4: Phosphorus (P) is a non-metal and does not have the ability to displace hydrogen from acids.

In contrast, Zinc (Zn) is a metal that is highly reactive with acids. It readily reacts with acids, such as hydrochloric acid (HCl), to form Zinc chloride (ZnCl2) and liberates hydrogen gas (H2). This reaction is an example of a displacement reaction in which the metal (Zinc) displaces hydrogen from the acid.

Therefore, the correct answer is option 3, Zinc (Zn), as it is the only element among the options that can replace hydrogen from acids to form salts.