i Dont know if you can use scratch due to the open source rule?

just release the .sb3 file to. I think that counts 

U can use it but u wont be eligible for the prizes bec u cant use visual scripting to win a prize 

Genuinelly just give a link to the scratch game, they could use see inside to check the code... but as some other guy said, if you use any form of block coding ir visual coding, you are unable to get the prize, this includes scratch