This is a question from Function and custom characters.
As the operation does not increase the value to 9 or 18,it is possibly an operation of division(/) OR multiplication(*).
Now,6-3 = 3 and 6/3=2 (which is less than 3)
=>Both the operations are possible to represent the operation.
Let us check the options now:
I . 2∆2 = 0 = > 2-2 = 0 yields the result but 2/2 doesn't and hence it is NOT True always
II. 2∆2 = 1=>2/2 = 1 yields the result but 2-2 doesn't and hence it is NOT True always
(ELIMINATE A,B,D,E at this stage and arrive at C as ANSWER)
Also, III. 4∆2 = 2=>4-2 = 2 and 4/2=2 yields the same result and hence it is ALWAYS True OPTION(C)