**Core Concept**
Temporomandibular joint (TMJ) disorders involve complex interactions between the mandibular condyle, articular disc, and surrounding soft tissues. These conditions can lead to a range of symptoms, including pain, limited mouth opening, and grating sensations during jaw movement.

**Why the Correct Answer is Right**
The symptoms described are characteristic of **Internal Derangement of the TMJ**, specifically the anterior displacement of the articular disc. This occurs when the disc moves forward, potentially leading to grating sensations and pain due to the abnormal contact between the disc and the joint surfaces. The limited mouth opening (trismus) is often a result of muscle spasms or inflammation in response to the disc displacement.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect because it does not accurately describe the symptoms of Internal Derangement of the TMJ. While pain and limited mouth opening may be present in other TMJ disorders, the grating sensation is a key feature of disc displacement.
**Option B:** This option might be a distractor, as it could refer to other TMJ disorders, such as osteoarthritis or rheumatoid arthritis. However, these conditions typically present with different symptoms, such as joint swelling or morning stiffness.
**Option C:** This option is unlikely to be correct, as it does not specifically describe the symptoms associated with Internal Derangement of the TMJ. While pain and limited mouth opening may be present in other conditions, the grating sensation is a distinctive feature of disc displacement.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the grating sensation in Internal Derangement of the TMJ is often accompanied by a palpable click or snap during jaw movement. This can be a useful clinical clue to diagnose disc displacement.

**Correct Answer:** B. Internal Derangement of the TMJ