Answer 1

A only waits 1000ms each time,while B waits 1500ms. So for example:
In t = 0 A will be printed and B will be printed.
In t = 1000 A will be printed.
In t = 1500 B will be printed.
In t = 2000 A will be printed.
In t= 3000 A will be printed, then B will be printed.
In t= 4000 A will be printed.
// now A is printed 5 times
In t = 4500 B will be printed.
Finall In t= 6000 B will be printed.

Then the output would be:
class A
method in class B
class A
method in class B
class A
class A
method in class B
class A
method in class B
method in class B