C) Fossil A is younger than the index fossil
Note: Usually (unless in special cases such as movements caused by earthquakes (plate shifting) or other causes, the older fossils would be found in the lower strata. in this case, because it is measuring how low a certain fossil is, the greater the number, the older it is. The Index fossil is found 460 meters below the ground. On the other hand, Fossil A is located 166 meters above the Index fossil, at 294 meters. Therefore, C is your best answer.
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