Identify one research variable from that problem - McDonald's Unhealthy foods

My home work is a group project and all i have to do is write a 250 or more word paragraph on the below highlighted topic. 

• Identify one research variable from that problem,

Below is the breakdown of the assignment that we have to do for this week. Lets shoot for 250 words each. . As stated last week, we agreed to describe a business problem at McDonald's; unhealthy foods. 

• Identify the name and description of the selected company,
• Describe the problem or opportunity at that company - 
  
  
• Identify one research variable from that problem,
• Describe the methods you would use for collecting a suitable sample of either qualitative or quantitative data for the variable (NOTE: do not actually collect any data)
• Analyze how you will know if the data collection method would generate valid and reliable data (Note: do not actually collect any data)
• Conclusion, Compile, Post 

NEED TO HAVE THIS DONE BY SUNDAY 5pm Eastern Time NYC