In MS Excel, cells can contain various types of data, including text, numbers, and formulas. To differentiate between these, a specific convention is followed.
The correct answer is Equal sign. When you want to perform a calculation or use a function in a cell, you must always begin the entry with an equal sign (=). This tells Excel that the subsequent characters form a formula that needs to be evaluated, rather than being treated as plain text or a numerical value.
First cell referenced is incorrect because while formulas often reference cells (e.g., =A1+B1), the equal sign must precede any reference. Parenthesis are used within formulas for grouping operations but do not initiate a formula. Quotation marks are used to denote text strings within formulas or for specific functions, not to start a formula itself.