Question

UV and RV are secant segments that intersect at point V.

Answer 1

we know that

The Intersecting Secant Theorem  states that when two secant lines intersect each other outside a circle, the products of their segments are equal

so

in this problem

$TV*UV=SV*RV$

we have

$TV=a\ units\\UV=12\ units\\SV=4\ units\\RV=9\ units$

substitute the values and solve for a

$a*12=4*9$

$a=36/12=3\ units$

therefore

the answer is

The length of TV is $3\ units$

Answer 2

The correct answer is D) 3 units