Coccyx is a triangular arrangement of bone, that makes up very
bottom position of spine below sacrum, and it is a bone and not
bony marking.
Option B is wrong because optic foramen is a bony marking and
is a passage through orbit of eye in the lesser wing of sphenoid,
through which optic nerve pass.
Option C is wrong because nasal conchae are small and thin
scroll shaped bony elements which forms the upper respiratory
tract.
Option D is wrong, iliac spine which include anterior superior
iliac spine is a bony prominence of iliac bone.
Option E is wrong because, head of femur is bony marking on the
femur bone.