$(a)$ True : The magnitude of a vector is a number. Hence, it is a scalar.

$(b)$ False : Each component of a vector is also a vector.

$(c)$ False : Total path length is a scalar quantity, whereas displacement is a vector quantity. Hence, the total path length is always greater than the magnitude of displacement. It becomes equal to the magnitude of displacement only when a particle is moving in a straight line.

$(d)$ True : It is because of the fact that the total path length is always greater than or equal to the magnitude of displacement of a particle.

$(e)$ True : Three vectors, which do not lie in a plane, cannot be represented by the sides of a triangle taken in the same order.