The correct answer is A. The end parenthesis should be placed before the period.
Step-by-step explanation:
According to the MLA manual and other manuals used for writing academical papers, if you use information or ideas taken from an external source or author while writing a paper it is always necessary to acknowledge the authorship of the information. Because of this, during in-text citations, in which you quote, summarize or paraphrase another author the last name of the author and the page where the information appear in the original source should be included either by presenting both elements in parenthesis without any internal punctuation or by providing the last name of the author during the text and the page in parentheses at the end of the citation, this includes books, articles and any other document that has both a recognized author and numbered pages.
Considering the previous ideas, in the case of the citation presented (Tishman 56.) the name of the author "Tishman" and the number page "56" have been included, which is correct according to most style manuals. However, the use of the period (.) inside the parentheses is not correct as internal punctuation should not be included and therefore the period should be placed outside the parenthesis. Therefore, the error in this in-text citation is that "the end parenthesis should be placed before the period".