Answer:
Option B
Explanation:
Let us consider that these right triangles form a sort of proportion among one another. If that is so, we can list out which sides of one triangle correspond to which side of the other triangle;
![BA and DE,\\AC and EC,\\BC and DC](https://img.qammunity.org/2021/formulas/mathematics/high-school/n7picqx2irxjaz0ge9gwm5bmqkzmq56god.png)
With this being said, it is given that BA = 84, and DE = 7. To prove that the could be proportional, let us form a like fraction;
![DE / BA =\\84 / 7 = \\12\\\\Conclusion, BA = 12 * DE\\Conclusion, Sides Of Triangle DEC = 12 * Sides Of Triangle BAC](https://img.qammunity.org/2021/formulas/mathematics/high-school/2ej3qu79th2nni1y8vd8knxfxvinv9xqv1.png)
With that, the length of AC in respect to EC can be represented as such;
![AC = 12 * EC,\\156 - x = 12 * x,\\156 - x = 12x,\\156 = 13x,\\\\x = 12](https://img.qammunity.org/2021/formulas/mathematics/high-school/l8chjjz1l24r3rwivg6j4k3nubi2ytcbvq.png)
![AC = 156 - x = 156 - 12 = 144](https://img.qammunity.org/2021/formulas/mathematics/high-school/zu7mbeu8e14azrbwchnp8w8cpstrmrwjiw.png)
Solution - Option B