Windows phone 7 local database

Question

I am building a windows phone 7 app which coding is to be done in c#. i want a robust,fast,lighter database for my app. my app has quiz. it must show the questions randomly from the database. so a local database is required so that the app run offline. the questions are generated randomly to the user. the questions with all the required possible options and the correct answer is stored in database. i want full step by step tutorial stating n explaining each step. thnx in advance