Answer:
d. 16
Step-by-step explanation:
AB and AD are tangents from external point A to the circle with center C.
Since, tangents drawn from external point to a circle are congruent.
[tex] \therefore \: AB = AD \\ \therefore \: 7x + 4 = 3x + 68 \\ \therefore \: 7x - 3x = 68 - 4 \\ \therefore \: 4x = 64 \\ \therefore \: x = \frac{64}{4} \\ \huge \red{ \boxed{\therefore \: x = 16}}[/tex]
