In the following English question, out of the four alternatives, select the option which best expresses the meaning of the idiom "to have a cast-iron stomach", referring to a person who can eat or drink almost anything.

Introduction / Context:
The idiom "to have a cast-iron stomach" is a colourful English expression used in everyday conversation. It does not literally refer to a stomach made of iron. Instead, it figuratively describes a person who can eat or drink almost anything without feeling sick, uncomfortable, or upset. This question tests your understanding of idiomatic language and your ability to choose the most accurate meaning from similar sounding alternatives.

Given Data / Assumptions:

• The key expression is "cast-iron stomach".
• We are looking for the meaning of an idiom, not a literal description.
• The correct option must match how native speakers commonly use this phrase.
• Context is usually about food, drink, and digestion.

Concept / Approach:
Idioms are fixed expressions whose meanings cannot be completely understood from the individual words. "Cast-iron" suggests something very strong, durable, and resistant to damage. When this is applied to "stomach", the image is of a stomach that is so strong that nothing upsets it. Therefore, the idea is not about greed, poison, or harsh words, but about being able to consume almost any kind of food or drink without any digestive problems.

Step-by-Step Solution:
Step 1: Focus on the literal image: a stomach made of cast iron would be very strong and resistant. Step 2: Recall common usage: people say "he has a cast-iron stomach" when someone can eat spicy, oily, stale, or unusual food without getting sick. Step 3: Compare each option with this idea of physical tolerance to food and drink. Step 4: Notice that option b directly mentions the ability "to eat or drink anything without any problems", which matches the idiom exactly. Step 5: Confirm that none of the other options describe digestive strength or resistance to food-related issues.

Verification / Alternative check:
You can verify the meaning by thinking of situations where the idiom is used. For example, if a person eats street food in many places without ever falling ill, friends might remark that he has a cast-iron stomach. The focus is always on the ability to digest anything comfortably. This aligns perfectly with option b and not with the other interpretations, which talk about greed, harsh words, or poison in life, which are unrelated to digestion.

Why Other Options Are Wrong:
Option a: "a very greedy person" talks about greed or wanting more, not about digestion or physical tolerance to food. Option c: "to be indifferent to harsh words" describes emotional toughness, not stomach strength. Option d: "to face so many difficulties in life that one now becomes immune to even poison" is overly dramatic and shifts the meaning to life struggles instead of eating and drinking.

Common Pitfalls:
Students sometimes confuse physical toughness in terms of health with emotional or mental toughness. Phrases like "hard-hearted" or "thick-skinned" refer to emotions, while "cast-iron stomach" refers specifically to digestion and food tolerance. Another common error is over interpreting the word "poison" and imagining life problems, which moves away from the idiomatic everyday usage. Always think about how the phrase is used in real life conversations.

Final Answer:
The idiom "to have a cast-iron stomach" means to be able to eat or drink anything without any problems.