Correct Answer - Option 4 : =
A formula always starts with an equal sign (=), which can be followed by numbers, math operators (such as a plus or minus sign), and functions, which can really expand the power of a formula.
All Excel formulas begin with an equal sign (=). After the equal symbol, you enter either a calculation or function. For example, to add up values in cells B1 through B5, you can either: Type the entire equation: =B1+B2+B3+B4+B5.
Hence the correct answer is =.