Final answer:
The Lithotomy position is the most commonly used positioning for pelvic exams, where the patient lies supine with hips and knees flexed and feet in stirrups, offering optimal access for the examination.
Step-by-step explanation:
The position most commonly used for pelvic exams is the Lithotomy position. In clinical settings, the lithotomy position involves the patient lying on their back (supine) with the hips and knees flexed, thighs apart, and feet placed in stirrups. This position allows the healthcare provider optimal access to the pelvic organs for examination, collection of samples for cervical cytology, and other procedures. The Fowler's, Trendelenburg's, Sims', and Jackknife positions are used for different circumstances and procedures but are not specifically designed for pelvic examinations. None of the descriptions provided in options b, c, and d correspond to the lithotomy position.