iRoot v3.2.2_160623_1015 (One Click Root)
Requirements: 2.2 and up
Overview: The best free android root app in the world!

Highest Success Rate
The advanced android root engine and secure
android root technique make the success
rate more than 90%.

Support almost all android... http://www.apkformod.com/iroot-v3-2-2_160623_1015-one-click-root/