**Core Concept**
The Card test, also known as the Card's test or Card's compression test, is a clinical examination technique used to assess the integrity of the anterior cruciate ligament (ACL) in the knee joint. It involves applying a valgus stress to the knee while the patient is in a long sitting position, and observing the amount of movement or laxity in the knee.

**Why the Correct Answer is Right**
The Card test is specifically used to assess the integrity of the ACL by evaluating the degree of knee laxity in response to a valgus stress. When the ACL is intact, the knee should resist the valgus stress, and the tibia should not move excessively. However, if the ACL is damaged, the tibia will move more than normal, indicating laxity. This test is useful in the clinical setting to help diagnose ACL injuries.

**Why Each Wrong Option is Incorrect**
* **Option A:** The Card test is not used to assess the integrity of the posterior cruciate ligament (PCL). The PCL is a separate ligament that provides stability to the knee joint, and it is assessed using different clinical examination techniques.
* **Option B:** The Card test is not a test for meniscal injuries. While meniscal injuries can cause knee pain and instability, the Card test is specifically used to assess the integrity of the ACL.
* **Option C:** The Card test is not a test for ligamentous laxity in general. While ligamentous laxity can be a sign of various injuries or conditions, the Card test is specifically used to assess the ACL.

**Clinical Pearl / High-Yield Fact**
The Card test is a useful clinical examination technique for diagnosing ACL injuries, but it is not the only test used to assess ACL integrity. A thorough physical examination and diagnostic imaging studies may be necessary to confirm the diagnosis.

**Correct Answer:** A. Card test is done for ACL (anterior cruciate ligament) injury.