Which of the following is an example of ancillary services?

Ancillary services refer to a variety of supportive services that are essential in the diagnosis and treatment of patients, typically complementing primary healthcare. Each of the examples provided falls under the category of ancillary services.

Radiology encompasses imaging services such as X-rays, MRIs, and CT scans, which are critical for diagnosing conditions and guiding treatment. Laboratory services involve the analysis of specimens to support diagnoses, such as blood tests or biopsies. Physical therapy aids in rehabilitation and recovery from injuries or surgeries, enhancing a patient's functional abilities.

Since all three options—radiology, laboratory, and physical therapy—serve as supportive services integral to patient care, they collectively represent the comprehensive scope of ancillary services. Thus, the inclusion of all these examples leads to the conclusion that "All of the above" is indeed the correct answer.