Option A: এন্ডোডার্ম - Incorrect. The endoderm is involved in forming internal organs, not the skeleton. \nOption B: মেসোডার্ম - Correct. The mesoderm gives rise to the skeletal system. \nOption C: এক্টোডার্ম - Incorrect. The ectoderm forms the skin and nervous system. \nOption D: কোনটিই নয় - Incorrect. Option B is the correct answer. \nNote: The mesoderm is the layer responsible for the development of bones, muscles, and other structures.