. Abacus was the first
A: electronic computer
B: mechanical computer
C: electronic calculator
D: mechanical calculator
- The earliest mechanical calculator was the abacus.
- The blind make use of it. Individuals who are blind typically utilize a Cranmer abacus, a customized abacus designed by Tim Cranmer.
- A piece of soft cloth or rubber is put behind the beads to prevent them from moving unintentionally.
Hence, Option (D) is correct i.e. Mechanical Calculator.