The ratio of force to area, is defined as stress or pressure. (A) $\mathrm{F} / \mathrm{a}$ B) $F / A$ C) $A / F$ D) $a / F$

Step 1 ：The ratio of force to area, is defined as stress or pressure.

Step 2 ：The correct formula for stress or pressure is represented by \(\frac{F}{A}\)

Step 3 ：Final Answer: \(\boxed{\frac{F}{A}}\)