Answer:
The correct answer is "Place a proton above the original path".
Step-by-step explanation:
Proton pathways are used in different physical applications for medical and diagnostics systems such as proton-computed tomographies and other radiologies. A way to modify a fired proton's path downwards in these systems is to place another proton above the original path. Protons repel each other in the opposite direction for having the same charge, therefore, a proton placed above the path of another proton would change its path downward.