During ultrasonic testing by the immersion method, it is frequently necessary to angulate the search unit when a discontinuity is located at an angle in order to:

• A. Avoid a large number of back reflections that could interfere with a normal test pattern
• B. Obtain a maximum response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam
• C. Obtain a discontinuity indication of the same height as the indication from the flat bottomed hole in a reference block
• D. Obtain the maximum number of entry surface reflections