Why Can T I Root My Samsung Galaxy S4

I want to root my Samsung Galaxy S4 (see details below). After researching a lot, I thought TowelRoot would be the easiest option. So, after downloading the APK (v3 of Towelroot) and trying to ‘make it ra1n’, the app said that my device was not compatible. I even tried the ‘ModStrings’ codes. So are their any other options for rooting on a Mac? If so how would one root?

Thanks a lot!