To find the total floor area of all the offices, you need to multiply the number of offices by the floor area of each office.
The correct equation is:
\[ 23 \times 305 = n \]
Now, let's calculate the value of \( n \):
\[ 23 \times 305 = 7,015 \]
Therefore, the correct response is:
\[ 23 \times 305 = n, n = 7,015 \text{ square feet} \]