Question: Which formula calculates the total value of a single row of cells across a range of columns?

1. `=SUBTOTAL(C1:Y15)`
2. `=SUM(15L:15Z)`
3. `=SUM(C15:Y15)`
4. `=SUM(C11:C35)`

Answer: The correct answer of the above question is Option C:`=SUM(C15:Y15)`