Answer:
Option (C)
Explanation:
"If the two secants are drawn to a circle form an external points then the product of the measures of one secant segment (inside the circle) and its external segment will be equal to the product of measures of the other secant's segments."
By this property,
8(8 + x) = 9(9 + 7)
64 + 8x = 144
8x = 144 - 64
8x = 80
x = 10
Therefore, Option (C) will be the answer.