**Core Concept**
Ludwig's angina is a severe infection of the neck and floor of the mouth, characterized by rapidly spreading cellulitis. It involves multiple fascial spaces, which can become compromised, leading to airway obstruction and potentially life-threatening complications.

**Why the Correct Answer is Right**
The infection in Ludwig's angina typically spreads to the sublingual, submandibular, and submaxillary spaces. The sublingual space is located under the tongue, the submandibular space is situated below the mandible (lower jaw), and the submaxillary space is another term for the submandibular space. These spaces become involved due to the spread of infection from the floor of the mouth, leading to significant swelling and potential airway compromise.

**Why Each Wrong Option is Incorrect**
**Option A:** While the sublingual space is indeed involved in Ludwig's angina, it is not the only space involved.
**Option B:** Similarly, the submandibular space is also involved, but the question asks for all spaces involved, not just one.
**Option C:** The term "submaxillary" is sometimes used interchangeably with "submandibular," but this option is still incorrect because it does not encompass all spaces involved in Ludwig's angina.

**Clinical Pearl / High-Yield Fact**
Ludwig's angina is a medical emergency requiring prompt recognition and airway management. It is essential to identify the involved spaces and initiate appropriate treatment to prevent airway compromise and other complications.

**✓ Correct Answer: D. All of the above**