**Core Concept**
Anaemia in humans can be caused by various factors, including infections, genetic disorders, and infestations. In this context, we are looking at parasitic infections that lead to anaemia. The correct answer is related to a specific type of worm infection that affects the human body's ability to produce haemoglobin or red blood cells.

**Why the Correct Answer is Right**
The correct answer is linked to the infection caused by the *Ancylostoma duodenale*, also known as the hookworm. These worms attach to the intestinal wall and feed on the host's blood, leading to chronic blood loss. This results in iron deficiency anaemia due to the loss of iron from the digested blood. The worms also induce inflammation in the intestinal mucosa, further impairing the body's ability to absorb nutrients.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because *Taenia saginata*, the beef tapeworm, primarily causes malabsorption and weight loss rather than anaemia.
* **Option B:** This option is incorrect because *Ascaris lumbricoides*, the roundworm, can cause intestinal obstruction, but it is not typically associated with anaemia.
* **Option C:** This option is incorrect because *Trichuris trichiura*, the whipworm, can cause rectal prolapse and other gastrointestinal symptoms, but it is not a primary cause of anaemia.

**Clinical Pearl / High-Yield Fact**
Hookworm infections are a significant public health concern in tropical and subtropical regions, with millions of people worldwide infected. The infection is often asymptomatic, but it can lead to severe anaemia, especially in children and pregnant women.

**Correct Answer:** D.