Correct Option: A  [ Abacus ]
Remark:
The Abacus is considered the first calculating device in human history. It was invented around 2500 BCE and used in ancient civilizations such as China, Egypt, and Mesopotamia. The Abacus consists of beads that slide on rods or wires, representing numbers, and is used to perform basic arithmetic operations like addition, subtraction, multiplication, and division. It laid the foundation for modern computing and calculating tools.
Other options (for context)
- Calculator: A modern electronic device for computation, developed much later.
- Turing machine: A theoretical computational model proposed by Alan Turing in 1936.
- Pascaline: A mechanical calculator invented by Blaise Pascal in 1642, long after the Abacus.