In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture.
The correct answer is “C” ultrasound. Hope this helps!
Big band is music group (a group of people who perform instrumental and/or vocal music ) playing jazz or jazz-influenced popular music and which was popular during the Swing Era from the mid-1930s until the late 1940s. These big bands contained saxophones, trumpets, trombone and other instruments and typically consisted of approximately 12 to 25 musicians.