What symbol is used to insert a formula in a cell of a spreadsheet in Microsoft Excel?

The correct option is D $=$
We can create a simple formula to add, subtract, multiply or divide values in your worksheet. Simple formulas always start with an equal sign ($=$), followed by constants that are numeric values and calculation operators such as plus ($+$), minus ($-$), asterisk($\ast$), or forward slash ($/$) signs.

On the worksheet, click the cell in which we want to enter the formula. Type the $=$ (equal sign) followed by the constants and operators that we want to use in the calculation.