$A$ box when hung from a spring balance shows a reading of $50 \,kg$. If the same box is hung from the same spring balance inside an evacuated chamber,the reading on the scale will be

• A
  $50 \,kg$ because the mass of the box remains unchanged.
• B
  $50 \,kg$ because the effect of the absence of the atmosphere will be identical on the box and the spring balance.
• C
  less than $50 \,kg$ because the weight of the column of air on the box will be absent.
• D
  more than $50 \,kg$ because the atmospheric buoyancy force will be absent.