Which of the following is the earliest known calculating device?Select one:a.abacusb.Eniacc.Arpanetd.8086 processor

1. Break Down the Problem

We need to identify the earliest known calculating device among the provided options:

• a. abacus
• b. Eniac
• c. Arpanet
• d. 8086 processor

2. Relevant Concepts

• Abacus: An ancient calculating tool used for arithmetic processes.
• ENIAC: The Electronic Numerical Integrator and Computer, one of the earliest electronic general-purpose computers.
• Arpanet: A pioneering packet-switching network that later developed into the internet; not a calculating device.
• 8086 processor: An early microprocessor introduced by Intel in 1978.

3. Analysis and Detail

1. The abacus is used since ancient times, making it the oldest among the devices listed.
2. The ENIAC was developed in the 1940s and is significant in computing history but is not as ancient as the abacus.
3. The Arpanet is a networking infrastructure, not primarily a calculating device.
4. The 8086 processor is a modern microprocessor and significantly later than the others.

4. Verify and Summarize

The abacus, being a tool used since around 500 BC, clearly predates the others, which are 20th-century innovations.

Final Answer

The earliest known calculating device among the options is a. abacus.