Answer:
Option A, Olecranon
Step-by-step explanation:
The olecranon process is the U-shaped notch located on the proximal end of the ulna bone within the forearm, making the part of the body we know as the elbow. To protect this bone and its joints and ligaments with the distal humerus, a fluid-filled bursae lies between the bony process and the skin of the elbow. Because of its proximity to this bone structure, this bursa adopts the same name: olecranon bursa.
Prepatellar bursae are found above the patellar bones in the lower extremities. The prefix "pre-" means above or before, and patellar refers to the kneecap. This bursa provides a layer or protection and cushioning for the knee joint and the patella bone itself. It lies between this bone and the skin of the knee.
The subacromial bursae are superior to the humerus but inferior to the acromion process of the scapula, or shoulder bone. The prefix "sub-" means below, and acromial refers to this bony protrusion of the collar-turned-shoulder. This bone promotes free motion of the shoulder, allowing for adequate rotation while also decreasing friction preventing the two bones.
The trochanteric bursae are located lateral to the third trochanter and greater trochanter of the femur bones in the lower extremities. It lies between the soft tissues of the hip and the bones also reducing friction and preventing tissue injury in the event of abrasion.