**Core Concept**
The question is testing knowledge of a behavioral technique used to prevent habit disorders, specifically digit sucking, in mature children. This technique is an example of a non-pharmacological intervention aimed at modifying a patient's behavior.

**Why the Correct Answer is Right**
The alarm system is a reminder technique designed to alert the child when they are engaging in the habit of digit sucking. It works by attaching a device to the child's digit that emits an audible alarm when the child sucks on it. This technique was developed by Norton and Gellin, who recognized the importance of behavioral interventions in preventing habit disorders. The alarm system is a non-invasive and non-pharmacological approach that can be used in conjunction with other treatments to help children overcome digit sucking.

**Why Each Wrong Option is Incorrect**
**Option A:** Massler is known for his work on the development and eruption of teeth, but he is not associated with the alarm system for digit sucking.
**Option C:** Benjamin is a well-known figure in dental history, but he is not credited with the development of the alarm system.
**Option D:** Pinkham is a prominent figure in pediatric dentistry, but the alarm system for digit sucking is not attributed to him.

**Clinical Pearl / High-Yield Fact**
The alarm system is a non-invasive and non-pharmacological approach that can be used to prevent habit disorders in mature children. It is essential to consider behavioral interventions, such as the alarm system, as part of a comprehensive treatment plan for digit sucking and other habit disorders.

✓ Correct Answer: B. Norton and Gellin