The correct answer is:
A. They usually take several years to complete.
Explanation:
1. Certification programs are usually shorter in duration compared to traditional degree programs. They are designed to provide specific skills and training for a particular job or industry.
2. Unlike degree programs that can take several years to complete, certification programs are typically more focused and efficient in preparing individuals for specific roles.
3. Therefore, certification programs are known for their shorter duration rather than taking several years to complete.