In an experiment to estimate the volume of air in a soil sample using a measuring cylinder, it was found that:
initial volume of water .... = p cm₃
volume of soil before mixing with water = q cm₃
Final volume of water after adding soil = r cm₃
From the data above, which of the following deductions is correct?

• A.r = p + q
• B.r > p + q
• C.q = r - p
• D.r< p + q
• E.