Final answer:
The correct MLA formatting for a span of pages is 'pp. 350-75', following MLA guidelines for abbreviating page ranges.
Step-by-step explanation:
The correct way to list a span of pages according to MLA style is b.) pp. 350-75. In MLA documentation, when you are citing page ranges, you use 'pp.' followed by the page numbers with the omission of the repeated digits in the second number if they are the same as the beginning number when the second number is two or more digits long and does not start with a zero. For example, if a work spans the pages from 100 to 199, you would cite it as 'pp. 100-99'. This rule helps to keep the citation concise and clear.
MLA style uses the format of 'pages [starting page]-[ending page]' to indicate a span of pages. For example, if you are referring to pages 350 to 375, you would write it as 'pages 350-375'.