**Answer:**

The correct answer is option 'B' - nucleated and with haemoglobin.

Erythrocytes, also known as red blood cells, are an important component of the blood responsible for the transportation of oxygen throughout the body. While the structure and functions of erythrocytes are generally similar across species, there are some differences between human and frog erythrocytes.

**Nucleated Erythrocytes in Frogs:**
Frog erythrocytes are nucleated, meaning they contain a nucleus, whereas human erythrocytes are anucleated, meaning they do not have a nucleus. The presence of a nucleus in frog erythrocytes allows them to perform some additional functions that anucleated human erythrocytes cannot.

**Functions of Nucleated Erythrocytes in Frogs:**
1. Protein Synthesis: The nucleus in frog erythrocytes allows them to synthesize proteins required for various cellular processes.
2. Cellular Repair and Maintenance: Nucleated erythrocytes in frogs have the ability to repair and maintain themselves, which is essential for their long-term survival.

**Haemoglobin in Frog Erythrocytes:**
Both human and frog erythrocytes contain haemoglobin, a protein responsible for binding and transporting oxygen. Haemoglobin is the primary component of erythrocytes and gives them their red color. It allows the cells to carry oxygen from the lungs or gills to other tissues in the body.

**Differences in Size and Quantity:**
While the question does not explicitly mention the comparison of size and quantity between human and frog erythrocytes, it is important to note that there are indeed differences.
- Frog erythrocytes are generally smaller in size compared to human erythrocytes.
- Frogs have fewer erythrocytes in their blood compared to humans.

In conclusion, frog erythrocytes are nucleated and contain haemoglobin, similar to human erythrocytes. However, they are smaller in size and present in lower quantities compared to human erythrocytes.