Read the following passage and solve the questions based on it.
A business school publishes three issues of their research Journal in a year. The editor decided that the upcoming three issues April, August and December would carry articles written by seven of the most reputed professors of the school. Each of the seven authors (T, U, V, W, X, Y and Z) will have at least one article published but some may have more than one article published. The following restrictions apply to the publication of the articles:
(i) Each of the issues being prepared must contain at least two articles.
(ii) Only these seven professors’ articles can appear in the upcoming April, August and December issues.
(iii) No author may publish in each of the two consecutively published issues or twice in the same issue.
(iv) If an article written by T appears in an issue, then an article written by U must also appear in that issue.
(v) If an article written by W appears in an issue, then an article written by Y must appear in the immediately preceding issue.
(vi) An article written by Y cannot be published in an issue that contains an article written by Z.
If the December issue consists exclusively of articles written by U, V and W, then the August issue must have consisted of articles written by which of the following groups of authors?