With four denials you will need to convince the Officer why this degree is needed for your career plans in your home country. Having a job is good but the Officer must believe you aren't just doing this to find a way to the U.S. and then stay and that you truly have an intent to return.
Lynne R. Feldman, Attorney at Law
Concentrating in Immigration Law
2221 Camino Del Rio South, Suite 201
San Diego, CA 92108 | (619) 299-9600
Fax: (619) 923-3277
Former Adjunct Professor -- Immigration law
University of Illinois College of Law
You can reapply but I strongly recommend consulting an attorney. You need to provide lots of evidence that you will return to your home country.
Alexus P. Sham firstname.lastname@example.org (917) 498-9009. The above information is only general in nature and does not constitute legal advice. It does not create an attorney-client relationship.
Many experienced immigration attorneys offer Skype and other online media based consultations. May not be free, but would provide some information.
NYC EXPERIENCED IMMIGRATION ATTORNEYS www.myattorneyusa.com; email: email@example.com; Phone: (866) 456-8654; Fax: 212-964-0440; Cell: 212-202-0325. The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter.