Final answer:
Stereoscopic radiography is the technique that enables the determination of depth in a single radiographic image by simulating binocular vision with images taken from different angles.
Step-by-step explanation:
In the context of radiography, when dealing with a single radiographic image that presents only length and width, certain techniques can be used to measure the depth of a discontinuity in a thick object. Among the options provided, Stereoscopic radiography (A) is the technique employed for obtaining a three-dimensional perception of the object being examined from two radiographic images taken from different angles. This technique simulates the natural binocular vision of human eyes and allows for the determination of depth.
While ultrasonography (B) can be used to view the inside of the body in real-time and computed tomography (CT) scans can use the relative absorption of x-rays along different directions to produce a detailed image, neither of these methods is specifically called Stereoscopic radiography. For depth perception in a single image, the stereoscopic method is more relevant.