Answer:
The correct option is 'Using parasites for biological control of pests to increase crop yields.'
Explanation:
Using The method of biological control for killing pests is better than using a chemical control. Chemical controls such as pesticides can lead to the pests developing resistant genes against the pesticides. As a result, the pesticides will no longer be useful for killing pests. Hence, killing of pest through biological controls is a better method. For example, the usage of parasites for killing a certain kind of pest. This will increase the crop yield.