**Core Concept**
The question is testing the knowledge of the upper limit of dietary fibre intake, which is essential for maintaining a healthy gut and preventing gastrointestinal complications. The American Heart Association recommends a daily intake of 25-30 grams of fibre for adults. However, excessive fibre consumption can lead to gastrointestinal symptoms and impair nutrient absorption.

**Why the Correct Answer is Right**
Consuming more than 50 grams of dietary fibre per day can cause gastrointestinal side effects, such as bloating, gas, and abdominal cramps. This is because a sudden increase in fibre intake can lead to an imbalance in gut microbiota and put a strain on the digestive system. The soluble and insoluble components of fibre can also interfere with the absorption of essential nutrients like calcium, iron, and magnesium.

**Why Each Wrong Option is Incorrect**
**Option A:** 10 grams - This is a very low level of fibre intake and is unlikely to cause harm. In fact, consuming this amount may not provide sufficient benefits for digestive health.
**Option B:** 30 grams - While this is a recommended daily intake, it is not considered excessive and is unlikely to cause harm to most individuals.
**Option C:** 100 grams - This is an extremely high level of fibre intake and is likely to cause severe gastrointestinal symptoms, including constipation, diarrhea, and abdominal pain.

**Clinical Pearl / High-Yield Fact**
It is essential to increase fibre intake gradually to allow the gut microbiota to adapt and prevent gastrointestinal symptoms. A sudden increase in fibre intake can lead to an imbalance in gut microbiota and impair nutrient absorption.

**Correct Answer:** C. 50 grams