Which option best describes a condition that is not one of the three primary x-ray machine controls?

• A. kVp, mA, time
• B. kVp, mAs, distance
• C. kVp, mA, distance
• D. mA, time, distance

Answer: (B)

The key idea is identifying which items are the three primary x-ray machine controls. Those three are kilovoltage peak (kVp), milliamperage (mA), and exposure time, with milliampere-seconds (mAs) being a product of mA and time rather than an independent primary control. Distance affects beam intensity but is not a primary control you set on the console.

The option that lists kVp, mAs, and distance shows a combination that is not the standard trio because it replaces the separate exposure-time control with a derived quantity (mAs) and adds distance. This makes it clearly not one of the three primary controls. The other possibilities either present the exact primary trio or mix distance with primary controls in a way that doesn’t as clearly illustrate the non-primary nature of mAs.