A freshly unfertilized egg of hen contains

The correct option is "one cell".

An egg cell, or ovum, is the female gamete (reproductive cell) in animals, including birds like the hen. Before fertilization takes place, the egg consists of a single unfertilized haploid cell. Even though a hen's egg is quite large because it contains a massive amount of yolk (nutrient reserve) to support potential embryo development, it remains a single cell until fertilization occurs.
Once fertilization happens, the single-celled zygote begins to divide rapidly (undergoing cleavage) to form a multicellular embryo. However, a freshly unfertilized egg has not undergone any cell division and therefore contains only one cell.