None of the alternatives are correct. The domain's lower bound is 6, however it contains 6, therefore a bracket is required rather than a parenthesis. [6 (infinity)] Because infinity is not included, a bracket for infinity is invalid. The range is from 0 to infinity. assuming you meant 1/sqr (x-6). However, none of the options are right if you meant 1/(sqr(x) - 6).
or did you mean 1/sqrx - 6? However, none of them are correct.