Answer:
D. 25
Explanation:
The left end of the baseline has measure (x-16). In this geometry all of the right triangles are similar, so the short-to-long side ratios are proportional:
(x -16)/12 = 12/16
x -16 = 9 . . . . . . . multiply by 12
x = 25 . . . . . . . . . add 16
The unknown length x is 25.