使用C＃存储数据的正确方法

I'm currently designing a Windows desktop application to manage a lot of tasks for my church, but currently I'm stopped at how to keep proper data for these tasks. I don't want to connect to a remote server to store data (i.e. MySQL, or MSQL) and I prefer not to use JSON, or XML unless fully necessary. There would be some 150-500 rows of data with maybe 40-50 columns of data for each row, and an unknown amount of data in each column. I know how to do this with MySQL, but I don't want to do that unless it truly becomes necessary. Basically, are there any other alternatives? Or is MySQL just going to be the best way?I'm currently designing a Windows desktop appli