A company wants to study the effectiveness of new pain relief medicine. They recruit 100100100 volunteers who suffer chronic pain. Half of the 505050 males are randomly assigned to the treatment group, and the other half are assigned to the control group. The same method is used to randomly assign half of the 505050 females to the treatment group and the other half to the control group.

What type of experiment design is this?
A) Matched Pairs
B) Stratified
C) Completely randomized
D) Systematic
E) Randomized Block