The most relevant evidence that acid deposition is to blame for damage to the trees would be:
c. the soil contains high levels of aluminum.
Step-by-step explanation:
- Acid deposition can lead to increased aluminum levels in the soil. When rain combines with sulfur dioxide and nitrogen oxides in the atmosphere, it can form acid rain, which in turn can leach aluminum from the soil. High aluminum levels can harm tree roots and affect their health. Therefore, this evidence is more directly related to the potential impact of acid deposition on the trees.
The other options (a, b, and d) are not as directly linked to acid deposition's effects on tree health.