**Core Concept**
Anemia of chronic renal failure is a condition characterized by a decrease in red blood cell production, leading to reduced hemoglobin levels. This occurs due to the inadequate production of erythropoietin (EPO) by the kidneys, which is essential for red blood cell production.

**Why the Correct Answer is Right**
The kidneys produce erythropoietin in response to hypoxia, which stimulates red blood cell production in the bone marrow. In chronic renal failure, the kidneys are unable to produce sufficient EPO, resulting in anemia. Erythropoietin therapy can improve symptoms by stimulating red blood cell production. However, dialysis itself does not directly cause severe anemia, but rather, it can lead to inflammation and oxidative stress, which can worsen anemia.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is correct, as anemia of chronic renal failure is indeed normocytic and normochromic.
**Option B:** This option is partially correct, but erythropoietin therapy improves the hematocrit level, not just symptoms. Symptoms such as fatigue, weakness, and shortness of breath are alleviated as a result of improved oxygen delivery to tissues.
**Option C:** This option is incorrect, as dialysis itself does not cause severe anemia. However, patients on dialysis may develop anemia due to chronic inflammation and oxidative stress.
**Option D:** This option is incorrect, as anemia in chronic renal failure is not proportional to the severity of kidney disease. Anemia can occur even in early stages of kidney disease, and its severity can be influenced by factors such as inflammation, iron deficiency, and vitamin deficiency.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that anemia in chronic renal failure is often multifactorial, involving not only EPO deficiency but also iron deficiency, inflammation, and oxidative stress. Early identification and treatment of anemia can improve quality of life and reduce morbidity in patients with chronic kidney disease.

**Correct Answer:** a) Normocytic normochromic anaemia