Which of the following alloys has a maximum percentage of Copper?

Which one of the following alloys contains a non-metal as one of its constituent?

Which among the following are constituents of brass?

Which one of the following metal is NOT an essential component in stainless steel?

Which of the following elements are included in stainless steel?

Alloy of which metal is used to make aeroplane and parts of the compartment of the train?