Answer:
C. Pesticides protect our crops, but some European countries have
linked them to thyroid disorders.
Explanation:
Researches involving human or sometimes animals are subject to critical decision making. 
They can easily trespass on the fundamental rights of people and some other issues. 
- The use of pesticides on a crop which can lead to thyroid disorder is an ethical dilemma. 
- In this case, the pesticide helps to prevent crop loss due to the invasion of pests. 
- This will boost food production and ensure food is available
- Likewise, the application of the pesticide causes thyroid issues. 
- This is an ethical dilemma issue.