Final answer:
Option A.
Anna's sediment sample, measuring 0.977 millimeters, falls within the grain size range for sand, which is 0.063 to 2 millimeters.
Step-by-step explanation:
The question pertains to the classification of a sediment sample based on its grain size.
Anna's sediment sample measures 0.977 millimeters in diameter, and according to standard geological classifications of sediment size, this falls within the size range for sand.
Sediment is typically sorted into different categories based on grain size, with clay being the finest (less than 0.0039 millimeters in diameter), silt being slightly coarser (0.0039 to 0.063 millimeters), sand being coarser still (0.063 to 2 millimeters), and gravel (2 millimeters to 6 centimeters), pebble (6 centimeters to 20 centimeters), and larger sizes extending up from there.
Therefore, the correct classification of Anna's sample is sand.