Answer:
Option C, An overall collapse of the food web as the herbicide would kill all producers and they are the base of any food web
Step-by-step explanation:
Addition of herbicide is not only harmful to the producers with in the lakes but all associated living organism. Herbicides will kill the producers and If the producers will die then the first level consumers will also die due to lack of food. Secondary consumers dependent on primary consumers will also die as they will not get sufficient food. Like wise, the tertiary consumers will also die. In this way the overall food web will collapse when herbicides are added to lake.
Hence, option C is correct.