Step 1: Understanding blood components.
Erythrocytes, or red blood cells, are the most numerous cells in the blood and are responsible for transporting oxygen. They make up the largest portion of the total blood cell count.
Step 2: Analyzing the options.
(A) erythrocytes: Correct — Erythrocytes are the most abundant cell type in the blood, making up about 99% of the blood corpuscles.
(B) eosinophils: Incorrect — Eosinophils are a type of white blood cell and are much less numerous than erythrocytes.
(C) lymphocytes: Incorrect — Lymphocytes are a type of white blood cell, but they are also less numerous than erythrocytes.
(D) thrombocytes: Incorrect — Thrombocytes, or platelets, are much less abundant than erythrocytes.
Step 3: Conclusion.
The correct answer is (A) erythrocytes, as they form the majority of blood cells.