What distinguishes a synchondrosis from other joint types, and why are both temporary and permanent synchondroses functionally classified as synarthroses? Select one: a. Synchondroses involve bone-to-bone connections, and their immobility is due to dense connective tissue. b. Synchondroses are characterized by free movement between bones due to synovial fluid, making them synarthroses. c. In synchondroses, bones are connected by hyaline cartilage, and their minimal movement classifies them as essentially immobile joints (synarthroses). d. Permanent synchondroses ossify over time, leading to increased mobility.