Final Answer:
a) =B13-C13 because The formula "=B13-C13" accurately calculates the difference between the values in cells B13 and C13, meeting the specified requirements without unnecessary complexity.
Step-by-step explanation:
The correct formula for cell B14 (copied to C14) is (a) =B13-C13. This formula subtracts the value in cell C13 from the value in cell B13. The subtraction operation is straightforward and aligns with the given choices.
Option (b) includes a SUM function unnecessarily, which could lead to inaccuracies or undesired results. Option (c) simply references cell B13 without performing any operation, and option (d) sums a range of cells from B6 to B13 without subtracting C13.
Therefore, option (a) is the accurate and concise formula for the specified task.