What is the smallest unit containing the entire human genome?

The correct answer is - One human somatic cell

Explanation:

Almost all the cell in the human body contains the same DNA with the same gene and each somatic cell contains the entire human genome. Every cell contains the same DNA but different genes are expressed in different cells that specify the function and structure of every cell.

For example, in only RBC the genes for hemoglobin protein will be expressed not in the cell present in the liver or any other organ. So one human somatic cell is the smallest unit that contain the entire human genome but not all the genome part is expressed in a single cell.