Mrs$.$ Johnson lets her students choose between two different word problems:

Problem A: If you are digging for dinosaurs and need to fence off your dig site, what's the biggest site you can fence off with $40ft.$ of fence?

Problem B: What is the largest area you can create with $20$ inches of rope?

Mrs$.$ Johnson finds a significant majority of her students chose to work Problem A$.$ Which of the following is the most likely reason more students chose Problem A instead of Problem B$?$

Problem B is less interesting than Problem A$.$

Problem B is harder than Problem A$.$

Students who work Problem A get a greater reward from Mrs$.$ Johnson than students who work Problem B$.$

Problem A requires a lower mathematical knowledge.