The correct way to cite the quote within the text of an essay according to MLA guidelines is A. "I wonder how many people I've looked at all my life and never seen" (Steinbeck 31).
In MLA format, it is standard to include the author's last name and the page number for in-text citations, and mentioning the full title of the work is not necessary when the author is already provided unless there are multiple works by the same author being cited.