what's the correct answer I'm so confused

Like before, we will calculate this by using ratios and because these two triangles are similar, which is very important.
Explanation:
We see that the TK = 65 corresponds to the MV = 30. Therefore, TU = 39 corresponds to the LM = x .
65 : 30 = 39 : x
x = (30*39)/65
x = 1170/65
x = 18.
The correct answer is C. 18.