Final answer:
The advantage of CVS over amniocentesis is that it provides earlier results, as it can be performed between the 10th and 13th weeks of pregnancy.
Step-by-step explanation:
The primary advantage of Chorionic Villus Sampling (CVS) over amniocentesis is a) Earlier results. CVS can be performed between the 10th and 13th weeks of pregnancy, allowing for earlier genetic testing and thus providing results sooner than amniocentesis, which is typically performed between the 15th and 18th weeks of pregnancy. This can be crucial for expecting parents when it comes to decision-making and preparation. Although CVS offers earlier results, it is important to consider that each procedure has its own risks and potential complications, and the decision between the two should be made in consultation with medical professionals.