The table shows the values of two quantities for an astronaut on earth and mars.

astronaut's details
earth mars
quantity a 735 units 279.75 units
quantity b 75 units 75 units

which of the following names the quantity and correctly explains why that represents the force exerted on the astronaut?

which quantity measures the force exerted on the astronaut?
quantity a, because it is independent of the location
quantity a, because it changes with gravitational pull
quantity b, because it remains unchanged in space
quantity b, because it is the quantity of matter present