Displaying Themes on website before purchase

What are the rules around displaying themeforest themes on your website for customers to choose from before you purchase and develop for them?

Are we allowed to display a thumbnail, with link to specific theme from themeforest demo? We would purchase the theme a client wants when they choose and then customize from there after we purchase.

We need to know what the rules are for this type of use.

Thanks!

yes, it is allowed. Also you can add a link to the themeforest theme page to check full details. Thanks