The correct answer is B. Erythrocyte.
An erythrocyte, also known as a red blood cell, is a type of blood cell that carries oxygen to the body’s tissues. It is a biconcave disc without a nucleus. The lack of a nucleus allows for more space for hemoglobin, the protein that carries oxygen.
A lymphocyte is a type of white blood cell that plays a role in the immune system. It is a nucleated cell that can differentiate into different types of cells, including B cells, T cells, and natural killer cells.
A spermatozoan, also known as a sperm cell, is a male gamete. It is a flagellated cell that is able to swim through the female reproductive tract to fertilize an egg. It is a nucleated cell.
An oocyte, also known as an egg cell, is a female gamete. It is a large, nucleated cell that is capable of being fertilized by a sperm cell.
In conclusion, the correct answer is B. Erythrocyte.