The correct option is A assimilation
The breakdown of larger complex biomolecules into their smaller, simpler and absorbable forms is known as digestion.
The process by which the end products of digestion pass through the mucosa of the digestive organs into the blood or lymph is called absorption.
The process by which absorbed nutrients finally reach the tissues which utilize them for their activities is known as assimilation.
The passing out of the undigested food material in the form of faeces is known as egestion or defecation.