Which s-block element is a silvery-white metal that is used in an alloy with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes, and non-sparking equipment?

Correct option is A

Beryllium is the s-block element that is a silvery-white metal used in an alloy with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes, and non-sparking equipment.
Beryllium alloys are notable for their high strength and lightweight, along with good thermal and electrical conductive properties.
Rubidium (Rb): This is a soft, silvery-white metal, but it's too reactive for the applications mentioned. It wouldn't be suitable for alloys used in high-stress environments.
Francium (Fr): This element is highly radioactive and extremely rare. It's not used in any practical applications due to its scarcity and instability.
Caesium (Cs): Caesium is also a soft metal, but it's not ideal for these applications. Similar to Rubidium, it's too reactive for the demanding conditions required in gyroscopes, springs, etc.