Sandra is conducting an investigation on soil. She poked several small holes in the bottoms of three plastic cups and filled one with sand, one with clay, and one with loam. She set each cup of soil inside a slightly smaller cup, like in the picture shown. She poured the same amount of water into each cup of soil and came back one hour later to measure how much water had dripped through each soil. The following amounts of water were found at the bottoms of the smaller cups. sand: 4ml
clay: 0ml
loam: 2.5ml

Based on this information, what was sandra MOST LIKELY investigating?
A. She was measuring how well each soil holds plants.
B. She was measuring the particle sizes found in each soil.
C. She was testing the ability of each type of soil to hold water.
D. She was measuring the amount of air found in each soil.