MCQ Medical Test Prep Website Development

Hello, I am looking for a professional web designer to create MCQs and their explanations website for medical tests that need preparation and the student od medicine can buy let us say 5000+ questions for the exam he is preparing for so he can solve the question in the website and read its explanation and which questions he solved right and which question he solved wrong and he can create different medical tests according to the subject of the questions. I am working on the website and I need only serious developers that gets paid after the website is completed. I insert the questions and answer and the explanation, we launch the website next year, so I want a company that not only create the website but stay in the future for further updates and to add other exams in the future so I want a company that stay. I am ready to pay fairly good if the work deserve so and in high quality. Only experienced developer gets accepted, contact me via mail and leave a number and which country and company so I can call and explain further because I am serious. I can tell you similar websites to build something similar.