Out of 'X' pairs of ribs in humans only'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation.

• A

   X = 12, Y = 5 ---True ribs are attached dorsally to vertebral column and sternum on the two ends.

• B

   X = 24, Y = 2 ---The true ribs are dorsally attached to vertebral column but are free on ventral side.

• C

  X = 24,Y = 12 ---True ribs are dorsally attached to vertberal column but are free on ventral side.

• D

  X = 12,Y = 7----True ribs are attached dorsally to vertebral column and ventrally to the sternum.