The columns and rows that Maria should select to unhide or show the hidden column C and hidden row 6 are C. B and D, 5 and 7.
What columns and rows should be selected?
Hidden column C is between columns B and D. To unhide it, Maria needs to select either column B or D. Also, hidden row 6 is between rows 5 and 7. To unhide it, Maria needs to select either row 5 or 7.
Therefore, Maria should select column C and row 5 or 7, which matches option C. Selecting E and F or 4 and 5 would not reveal the hidden column C or row 6. So, the best option is C.