Calling a class's constructor inside another class

Question

I have a test next week for c++ and I\'m preparing myself for it. I\'m confused when I have 2 classes as shown below. I have to walk through the execution of the code, line by l

Answer 1

from the line x = one(a, b); it jumps to line one(int a, int b) and executes the parameterized constructor of one

same for line y = one(c, d);