## **Core Concept**
The Periodontal Screening and Recording (PSR) system is a method used for quick and easy assessment of periodontal status. It involves the use of a special periodontal probe to measure the depth of periodontal pockets around teeth. The PSR system helps in identifying patients who require more detailed periodontal examination.

## **Why the Correct Answer is Right**
The correct answer is associated with a periodontal probe that has a **WHO** or **UNC** type of marking but specifically for PSR, a probe with **mm markings and a ball-ended tip** is utilized. This specific design facilitates easy measurement and reduces trauma to the gingiva. The **WHO periodontal probe** is commonly used for such screenings.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately describe the characteristics of a probe used for PSR.
- **Option B:** This option is incorrect as it also does not accurately represent the specific features required for a PSR probe.
- **Option D:** This option is incorrect because it does not match the description of a probe suitable for periodontal screening.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **WHO periodontal probe** is often used for PSR due to its **5 mm markings**, which help in quick assessment. This probe is an essential tool in periodontology for initial screenings.

## **Correct Answer:** .