Commercial Usage of Theme

Hi,

I really appreciate you have done a very nice theme and made available for free. Can I please know the commercial usage of this? I am building a site for my client using Business-elite theme, however some modifications will require. So can we download the theme from the given download link, edit it as much as we want (change the look of scrolling pages, add more pages, change animations etc) and upload it to our wordpress server as the client’s site?

Also if the above is possible, does it require to keep the sentence at the bottom of the site which says “WordPress Themes by Web-Dorado” ?