The first evidence of cartilage getting converted to bone in craniofacial skeleton occur during:

 # The first evidence of cartilage getting converted to bone in craniofacial skeleton occur during:

A. Fourth postnatal week

B. Eighth prenatal week

C. Fourth prenatal week

D. Eighth postnatal week

The first evidence of cartilage converting to bone (endochondral ossification) in the craniofacial skeleton occurs during the eighth prenatal week. This timing aligns with the development of the cranial base (e.g., occipital, sphenoid, and ethmoid bones), which undergoes endochondral ossification. While mesenchymal condensations and cartilage models form earlier, the actual replacement of cartilage by bone begins around this period, marking the start of ossification in these regions.

Answer: B. Eighth prenatal week