**Core Concept:** The question is asking about the milk type that has the minimum calcium content. In mammals, milk is primarily composed of calcium, which is essential for bone health and other physiological processes.

**Why the Correct Answer is Right:** Among the options provided, goat milk has the least amount of calcium. Goat milk contains lower calcium levels than cow, sheep, and buffalo milk due to its smaller size and lower fat content. Less fat means less calcium precipitation, resulting in lower calcium levels.

**Why Each Wrong Option is Incorrect:**

A. Cow milk: Calcium is more prevalent in cow milk compared to goat milk. Cow milk's larger fat globules allow for more calcium precipitation, leading to higher calcium levels.

B. Sheep milk: Sheep milk contains higher calcium levels than goat milk due to its larger fat globules, which facilitate calcium precipitation and increase calcium content.

C. Buffalo milk: Similar to sheep milk, buffalo milk has larger fat globules that enable more calcium precipitation, resulting in higher calcium levels compared to goat milk.

D. Human milk: Human milk has the highest calcium content among mammals due to its larger fat globules that facilitate calcium precipitation.

**Clinical Pearl / High-Yield Fact:** The calcium content in milk varies among species and is influenced by factors such as fat globule size and animal species. Familiarizing yourself with these variations can help guide dietary choices for calcium intake and ensure proper calcium absorption.

**Correct Answer:** D. Human milk contains the least amount of calcium compared to the other options.