**Core Concept:** Submicroscopic deletions are small genetic abnormalities that cannot be seen under a standard light microscope but can be detected using advanced molecular genetic techniques. These deletions can lead to various clinical manifestations depending on the size and location of the deletion.

**Why the Correct Answer is Right:** The correct answer is **D.** Polymerase Chain Reaction (PCR) is a molecular technique that amplifies specific DNA segments, allowing for the detection of submicroscopic deletions. By using PCR, researchers can identify the absence of a specific gene or DNA sequence, indicating a deletion.

**Why Each Wrong Option is Incorrect:**

A. **False.** Array Comparative Genomic Hybridization (aCGH) is a technique used to detect larger chromosomal abnormalities, not submicroscopic deletions.

B. **False.** Fluorescence In Situ Hybridization (FISH) is a technique used to identify specific chromosomes or gene loci, not detect submicroscopic deletions.

C. **False.** Southern Blotting is used to detect DNA fragment sizes and not suitable for detecting submicroscopic deletions.

**Clinical Pearl / High-Yield Fact:** Submicroscopic deletions are important to detect as they can lead to various clinical manifestations like developmental delay, intellectual disability, seizures, or specific diseases such as Williams syndrome and Cornelia de Lange syndrome. Understanding the correct technique for detecting these deletions is crucial for accurate diagnosis and appropriate management of affected individuals.