The proportion that can be used to compute p is
. So, the correct option is A.
The percent decrease (p) can be computed using the following proportion:
![\[\frac{\text{Decrease in value}}{\text{Original value}} = (p)/(100)\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/wxmmhypkppljujz800sp0l4wooigouih6y.png)
In this case, the original value is $32, and the decrease in value is $32 - $28. Substituting these values into the proportion:
![\[(32 - 28)/(32) = (p)/(100)\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/5zgmyab0ogowb1m1ia4y34djo106oxo6l1.png)
Therefore, the proportion that can be used to compute p is
.
Simplify the left side of the equation:
![\[(4)/(32) = (p)/(100)\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/rafmzomseyc5584s63h698b36hjn8qv576.png)
Reduce the fraction:
![\[(1)/(8) = (p)/(100)\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/uo9lvs21oy1o8mzljplmjyh6ta7ebhf320.png)
Now, you can solve for (p). Multiply both sides by 100:
![\[100 * (1)/(8) = p\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/k27cmhv3lcrvbl4a9qsvlhagk3adfla0ml.png)
![\[p = 12.5\]](https://img.qammunity.org/2021/formulas/mathematics/high-school/e5oiooyzbgussc1clslopkferu57z21m92.png)
Therefore, the percent decrease in the value of the stock is 12.5%.