Need to build an educational website, primarily MCQ based Test Taking

We need to get a website built for test taking purposes(essentially for students) The website must have the following features broadly: 1. MCQ based online tests for registered users with performance analysis after submission and, option to look for correct answers of wrong questions attempted by user. 2. Ability to choose the skill being tested from a list of given test skill options. 3. Questions can be text as well as picture based, so option for adding pictures/text both in questions as well as answer choices must be present. 4. Downloadable test paper section where question papers can be downloaded based on type of user subscription. 5. Subscriptions(Monthly, Quarterly and Annually) based on listed services. 6. User profiles with features like test history, scores, etc. 7. Payment gateway integration 8. Look and feel of the website is extremely important. 9. Easy to use, easy to navigate and logical structure for everyone. More details will be discussed later. Ongoing support for an year is essential.