1(a) Determine whether the argument is valid and give a reason why. It was either the oysters or the trout that made me sick. The test results are reliable and they say that it was not the trout, so it must have been the oysters. Select one: The argument is valid, it follows a valid form. The argument is invalid, something else could have made them sick. The argument is invalid, if the conclusion were false, one of the two premises would have to be false. The argument is valid, the conclusion is true. The argument is valid, but it might have been the trout, even if the premises were true. The argument is invalid, even if the premises were true, the conclusion could still be false