The concentric rings of calcified intercellular substance arranged around haversian
canals are called:
a) lamellae
b) lacunae
c) trabeculae
d) canaliculi
e) collagen fibers

The concentric rings of calcified intercellular substance arranged around Haversian  canals are called Lamellae

Explanation:

The microscopic tubes situating at the outer region of cortical bone which gives way to the nerves and blood vessels to travel through it is referred to as Haversian canals.  The channels of the canals are composed of concentric substance called Lamellae.

It surrounds the nerve cells and vessels of bones and makes a communication with cells of the bone through canaliculi. Lamellaes compose concentric rings made up of calcified intercellular substance around the tissue of bones.

the real answer is b. scintillation counter