**Core Concept**
The Beta-Oxidation cycle is a series of enzyme-catalyzed reactions that break down fatty acids into acetyl-CoA units, which can then be fed into the citric acid cycle to produce energy. This process is essential for the metabolism of fatty acids in the mitochondria.

**Why the Correct Answer is Right**
The correct answer is FADH2, which is generated during the Beta-Oxidation cycle. In this process, the fatty acid chain is broken down into two-carbon acetyl-CoA units, with each cycle producing one molecule of NADH and one molecule of FADH2. FADH2 is then used in the electron transport chain to generate ATP. The Beta-Oxidation cycle is initiated by the enzyme acyl-CoA dehydrogenase, which converts the acyl-CoA molecule into an enoyl-CoA molecule, resulting in the formation of FADH2.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not correct as it is not a product of the Beta-Oxidation cycle. The correct answer is FADH2.
**Option B:** This option is not correct as it is not a direct product of the Beta-Oxidation cycle. Although NADH is produced in the Beta-Oxidation cycle, it is not the correct answer in this case.
**Option D:** This option is not correct as it is not a product of the Beta-Oxidation cycle. The correct answer is FADH2.

**Clinical Pearl / High-Yield Fact**
In the context of mitochondrial disorders, defects in the Beta-Oxidation cycle can lead to the accumulation of fatty acids, resulting in conditions such as carnitine palmitoyltransferase (CPT) deficiency. This highlights the importance of the Beta-Oxidation cycle in maintaining normal fatty acid metabolism.

**Correct Answer: C. FADH2**