Answer:
D.144
Step-by-step explanation:
[tex]\frac{7}{x} = \frac{84}{156-x}[/tex]
⇔ 84x = -7x + 1092
⇔ 91x = 1092
⇔ x = 12
⇒ AC = 156 - x = 156 - 12 = 144
