Is Wordpress Theme built on Ocean WP or GeneratePress (free version) allowed on themeforest?

Hi Guys,

Want to sell WordPress templates in ThemeForest.

I know many developers code themes from zero and build option framework based on their requirements.

I definitely want to cut down this time consuming process.
So, can i build theme using WP Ocean or GeneratePress (FREE VERSION) and sell on Themeforest?

Been trying to play with underscores and Bootstrap but it seems like its going to take some time to code a quality theme.

Please help… your reply is very valuable.