**Core Concept**
The dorsal scapular nerve is a branch of the brachial plexus, specifically originating from the C5 root. It plays a crucial role in providing motor innervation to muscles of the scapular region. The nerve's primary function is to supply the rhomboids and the levator scapulae.

**Why the Correct Answer is Right**
The correct answer is related to the muscles innervated by the dorsal scapular nerve. The rhomboid major and minor, as well as the levator scapulae, are the primary muscles supplied by this nerve. The nerve's innervation enables these muscles to perform their actions, including scapular rotation, elevation, and depression.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the dorsal scapular nerve does not primarily supply the supraspinatus muscle, which is instead innervated by the suprascapular nerve.
**Option B:** This option is incorrect as the latissimus dorsi is supplied by the thoracodorsal nerve.
**Option D:** This option is also incorrect because the trapezius muscle is primarily innervated by the spinal accessory nerve.

**Clinical Pearl / High-Yield Fact**
The dorsal scapular nerve's dysfunction can lead to scapular winging, a condition where the scapula protrudes outward, affecting shoulder movement and stability.

**Correct Answer:** D. Rhomboids and levator scapulae.