In the SI system of units, the kilogram is the basic unit of mass.
In the 'customary' system, 'pound' can be either a unit of force or
a unit of mass. The way everybody uses it in everyday life ... like
your weight on the bathroom scale, or the weight of some apples
at the produce market ... it's used as a unit of force.
the other choices:
b). Newton . . . the SI unit of force, equal to about 0.225 pound
d). Cubic meter . . . a unit of volume