Loop-Invariant for a program fragment

Question

Q) Consider the following program fragment:

var x,y:integer;  
x:=1; y:=0;  
while y < x do  
begin  
  x:=2∗x;  
  y:=y+1;  
end;

For the above fragment , which of the following is a loop-invariant ?

A) x=y+1
B) x=(y+1)²
C) x=(y+1)2^y
D) x=2^y
E) None of the above, since the loop does not terminate

Since, Loop-Invariant is something which is true before and after each iteration of a loop. So, according to the definition, I am getting answer as (D) but I have a doubt whether termination of that loop is necessary or not for the given code. One of the properties of algorithm says :- algorithm should always terminate after finite no. of steps. So, if the question is about Pseudocode then I will definitely mark answer as (D) but since it is program fragment, So I am confused between options (D) and (E).
So, My Doubt is definition of loop-invariant is also true for the loop in the code which is written in any language like C,C++ etc.
Please help.