**Core Concept**
Acetylation of histones is a type of epigenetic modification that plays a crucial role in regulating gene expression. This process involves the addition of an acetyl group to the lysine residue of histone proteins, which are the main protein components of chromatin. By altering the charge and conformation of histones, acetylation promotes a more open chromatin structure, facilitating transcription and gene expression.

**Why the Correct Answer is Right**
The acetylation of histones is mediated by histone acetyltransferases (HATs), which transfer an acetyl group from acetyl-CoA to the lysine residue of histones. This modification results in the neutralization of the positive charge on the lysine residue, leading to a more open and relaxed chromatin structure. The increased accessibility of DNA to transcription factors and other regulatory proteins promotes the transcription of genes, making acetylation of histones a key epigenetic mechanism for gene regulation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because acetylation of histones does not result in the methylation of histones. Methylation of histones is a different type of epigenetic modification that can have opposite effects on gene expression.
**Option B:** This option is incorrect because histone phosphorylation is a different type of post-translational modification that can also regulate gene expression, but it is not the result of acetylation of histones.
**Option C:** This option is incorrect because histone ubiquitination is a different type of post-translational modification that can mark histones for degradation or other cellular processes, but it is not the direct result of acetylation of histones.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that epigenetic modifications, such as acetylation of histones, can be influenced by various factors, including environmental exposures, lifestyle choices, and disease states. Understanding these mechanisms can provide valuable insights into the development and progression of various diseases, including cancer.

**Correct Answer:** C.