Answer: C. Above the kingdom level
Explanation:
Hierarchical classification can be defined as the system of grouping living beings according to the level or orders. Domain secures the highest taxonomic rank in the biological hierarchical classification system. This lies above the Kingdom level. The life forms are classified into three domains, which are Archea, Eukarya and Bacteria.
They are absorbed in the small intestine, but I am not 100% sure if it is in the beginning or the middle.