Here's a problem to solve: Several students are entering a bridge building contest that requires using ice cream sticks and glue to construct the strongest bridge possible. The bridges must be 5 in. wide and span a length of 18 in. Which of the following tests is the most accurate way to determine the strongest span design for these bridges?

Among the 4 following options, which is the correct answer?

- A: roll toy cars across each bridge until it collapses
 
- B: place concrete construction blocks on top of each bridge until it collapses
 
- C: stack coins on both ends of each bridge until it collapses
 
- D: place D-cell batteries at the center of each bridge until it collapses
 