S/W Quality Assurance Interview Question:

If the pseudo code below were a programming language ,how many tests are required to achieve 100% statement coverage?
1.if x=3 then
2. display_messagex;
3. if y=2 then
4. display_messagey;
5. else
6. display_messagez;
7.else
8. display_messagez;

Submitted by: Sudha

C. 3

But I want to know why 3 test cases to cover 100% Statement coverage. Anyone please explain.
Thanks
Submitted by: Sudha