The simple in-text citation includes the surname of the authors, then the year of publication and at the end is the page number of the citation. The in-text citation is always placed at the end of the sentence. This means that the mistake is not including the year of publication and placing the citation at the end of the sentence. So in the nutshell the correct answer here is option A (Not including the year of publication) and option B (Placing the in-text citation in the wrong place).
