Extract data from Excel

In my offline quiz app almost 10000 Questions.I want store the excel in my app and extract data.How is it possible?Is there any alternative way for Such database(Offline)

I Know about an extension on Excel but its price is very high!

Always search here before asking about an extension you need.

I searched but there listed extension is high price(35dollors)

Convert it to JSON and save it as a string and use