The cells responsible for bone resorption are
osteoclasts
osteoblasts
fibroblasts
osteocytes

osteoclasts

Explanation:

Osteoclast is a cell that makes up the bone matrix, quite large compared to other cells, multinucleated, and is involved in resorption and remodeling of bone tissue. It has a lysosome-rich cytoplasm, numerous mitochondria, and a highly developed Golgi complex.

Although it was once believed that osteoclasts came from osteoprogenitor cells, they are now known to come from bone marrow derived from coalescent monocytes.

a = executive branch; b = judicial branch