Final answer:
The correct Excel MID function to extract the phrase 'entered the server room at' using the location of the '#' symbol in cell C4 is '=MID(C2, C4 + 1, LEN(C2) - C4 - 4)'. This accounts for the position after '#' and excludes the ' HH' from the string length calculation.
Step-by-step explanation:
The MID function in Excel is used to return a specific number of characters from a text string, starting at the position you specify. The question focuses on extracting the phrase 'entered the server room at' from a larger string in cell C2. To do this, we must use the location of the '#' symbol in cell C4 as the starting position (start_num argument) and calculate the number of characters to return using the length of the original string (LEN(C2)), adjusted for the position of '#' and the characters ' HH'.
After analyzing the options and understanding the requirements, the correct formula is: =MID(C2, C4 + 1, LEN(C2) - C4 - 4). This formula starts extracting 1 character after the '#' symbol and returns the correct number of characters by subtracting the starting position and additional 4 characters for the length of ' HH' and the '#' character itself from the total length of the original string.