Which is not required for visualisation of gallbladder in oral cholecystography –: (A) Functioning liver, (B) Motor mechanisms of gall bladder, (C) Patency of cystic duct, (D) Ability to absorb water
Answer is B. Visualization of the gallbladder in OCG depends on:-

Ingestion of dye
Absorption of dye in gut
Blood flow to liver (Entero-hepatic-circulation)
Take up in liver (functional liver), ability of liver to excrete dye into the bile (functional liver)
The ability of gallbladder to concentrate the excreted dye (by absorbing water)
Patency of hepatic & cystic duct system