Question

A dimensionless quantity

(a) never has a unit
(b) always has a unit
(c) may have a unit
(d) does not exist.

Answer 1

THE ANSWER IS THE LETTER A

Answer 2

A dimensionless quantity A. NEVER HAS A UNIT.

Dimensionless quantity is a quantity with the dimensions of 1. It is a quantity without physical unit. It is identified as a pure number. It may be a product or a ratio of quantities with units but all unit is cancelled out.