A. it Compare the variable a and the variable b are same.
B. The value of b is assigned to variable a but if b changes later, it will not effect the value of variable a.
C. The value of b is assigned to variable a but if b changes later, it will effect the value of variable a.
D. The value of variable a is assigned to variable b, and the value of variable b is assigned to variable a.

Solution

B. The value of b is assigned to variable a but if b changes later, it will not effect the value of variable a.