Answer:
c
Step-by-step explanation:
Substitute goods are goods that can be used in place of another good.
carbonated sodas are considered to be unhealthy and premium water is considered to be health. If consumers reduce consumption of carbonated sodas, they would want to consume something more healthy. This can be water. thus, the goods are substitutes
Complementary goods are goods that are consumed together
If the demand for carbonated sodas decreases, there would be an increase in demand for premium water