Mass is a ______ quantity.
A. Scalar
B. Vector
C. Tensor
D. None

Hint:The amount of matter present in a body is described as mass. It is the same everywhere in the universe. It can be considered as the combination of total number of atoms present in the body, density of these atoms and the type of atoms present in the body. Mass is a fundamental quantity in physics. It is independent of parameters such as temperature, pressure and the location of the object.

Complete answer:
A scalar quantity is the physical quantity that has only magnitude and needs no other information to specify it. The scalar quantities can be described by only numerical values along with their respective units. These quantities do not require any direction for describing them. The other examples of scalar quantities include temperature, density, length, are, volume, energy and pressure. A vector quantity is a physical quantity that requires both magnitude and direction to specify it. Force is the vector quantity.
Mass is categorized as a scalar quantity as it requires only its magnitude to describe it, but does not require its direction. The mass of 1 Kg object will be the same as that on the moon too. The SI unit of mass is kilograms or Kg. Mass can never be zero.

Mass is a scalar quantity.Hence, the correct option is option A.

Note:Though mass of an object is a scalar quantity, the weight of an object is a vector quantity. Weight of an object is the force of gravity that acts on an object. The formula for calculating weight of an object is given as,
$W = m \times g$
Here, $W$ is the weight of an object, m is the mass of an object and g is the acceleration due to gravity. Mass of an object is a scalar quantity but acceleration due to gravity is a vector quantity. Hence, weight of an object is categorized as a vector quantity.