The lungs are protected by
A) Breast bone
B) Ribs on sides
C) Vertebral column
D) All of the above

Hint: The lungs are a duo of spongy, air-filled organs situated on both sides of the chest (thorax). The windpipe conducts intake air into the lungs via its tubular divisions, known as bronchi. The bronchi then split into smaller and lesser branches (bronchioles), lastly becoming microscopic.

Complete answer:
The thoracic cage (rib cage) is the frame of the thoracic wall. It is created by the 12 thoracic vertebrae, 12 pairs of ribs and linked costal cartilages and the breastbone.
The thoracic cavity is surrounded by the ribcage and holds the lungs and the heart, which is situated in the mediastinum. In the thorax of most vertebrates, the configuration of the ribs attached to the vertebral column and sternum is known as the rib cage, which encircles and protects the heart and lungs.
The vertebral column provides muscle attachments, protects the trunk, preserves the spinal cord and nerve roots, and functions as a hemopoiesis site.
In human beings, the rib cage is a bony and cartilaginous structure that encases the thoracic cavity and bears the shoulder girdle to structure the center part of the human skeleton. The rib cage forms the thoracic wall together with the skin and related fascia and muscles and provides linkage for the thorax, upper abdomen, neck, and back muscles.

Hence, the correct option is D.

Note: Mainly ribs are the bony skeleton of the thoracic cavity. The ribs form the chief structure of the thoracic cage protecting the thoracic organs; however, their major function is to facilitate respiration. The other main function of the vertebral column in the defense of the spinal cord along with the protection of lungs; it also offers to stiffen the body and attachment for the pectoral and pelvic girdles and loads of muscles.