Select the correct option. A. 11th and 12th pairs of ribs are connected to the sternum with the help of hyaline cartilage. B. 8th, 9th and 10th pairs of ribs articulate directly with the sternum. C. Each rib is a flat thin bone and all the ribs are connected dorsally to the thoracic vertebrae and ventrally to the sternum. D. There are seven pairs of vertebrosternal, three pairs of vertebrochondral and two pairs of vertebral ribs.

Correct option is D. There are seven pairs of vertebrosternal, three pairs of vertebrochondral and two pairs of vertebral ribs. Vertebrosternal ribs are true ribs, dorsally they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. First, seven pairs of ribs are called true ribs. The 8th, 9th 10th pair of ribs do not articulate directly with the sternum but join the seventh ribs with the help of hyaline cartilage. These are vertebrochondral or false ribs. The last 2 pairs i.e., 11th 12th ribs are not connected ventrally and are, therefore, called floating ribs. Only the first seven pairs of ribs are ventrally connected to the sternum. So, the correct answer is 'There are seven pairs of vertebrosternal, three pairs of vertebrochondral and two pairs of vertebral ribs'