The correct option is D iv, iii, i, ii
There are 4 steps that occur during the process of nutrition in frogs: ingestion, digestion, absorption, egestion.
During ingestion, the food is taken in with the help of a bilobed tongue. The complex macromolecules in the food are broken down into simple absorbable micromolecules during the process of digestion. The partially digested food (chyme) reaches the small intestine from the stomach. In small intestine, bile salts emulsify fats and the pacreatic juices digest carbohydrates, proteins and fats. The micromolecules formed after digestion are absorbed into the body with the help of villi and microvilli. The undigested food enters the rectum and passes outside the body through cloaca. This process of removal of undigested wastes is called egestion.
Hence the correct sequence of steps involved in the process of nutrition are ingestion, digestion, absorption and egestion.